PEER REVIEW COMMENTS- SUN CQ
Anonymous referees’ comments .......................................................................................... 1
Monographs ............................................................................................................................. 1
Regular Articles ..................................................................... Error! Bookmark not defined.
2. peers’ correspondences .................................................................................................. 40
3. Editor’s choice ................................................................................................................... 46
4. PhD Thesis ........................................................................................................................ 47
Anonymous referees’ comments
Monographs
2.
The Soul of Water: Top Ten Mysteries, Springer Ser in Chem Phys 2016
I have read the introductory material and sample chapter on the slipperiness of ice. This is a
very unusual and interesting book. At first I thought from its entertaining and folksy style that
it would not be substantial enough for the Springer Chem. Phys. series, but it quickly moves
on to a deep discussion and thorough review of the topic. I personally found it very
interesting (my first degree was actually in chemistry before I moved on to physics). If the
other chapters are equally interesting, then there will likely be a substantial market for this
book. It would be great for students who are new to the topic. I wouldn't mind having a copy
for myself. The one problem is that the English needs to be improved, but it is
understandable as it is. On that basis, I can recommend it for the Springer Chem. Phys.
series.
1. Relaxation of the Chemical Bond- Springer series in Chem Phys 108, 2004
I have read the proposal with great interest, excitement and enthusiasm. It is very exciting to
have such unprecedentedly comprehensive monograph focused on the relaxation of
chemical bonds which is a truly universal phenomenon, yet not comprehensively and
critically addressed in any monographs that I am aware of. The author is a world-renowned
expert in several relevant fields and wrote several highly-successful and highly-cited reviews,
including the review in the top journal in Chemistry. Therefore, publication of this monograph
is recommended without any reservation.
Coordination-resolved Electron Spectrometrics, Chemical Reviews, 2015, 115, 6746-6810.
Dear Dr. Sun:
We are pleased to inform you that your manuscript has been accepted for publication and
sent to the Production Department. This is clearly an outstanding manuscript and we are
pleased to have the opportunity to publish it. Publication has been scheduled for an
upcoming regular issue of Chemical Reviews.
Sincerely,
Dr. Sharon Hammes-Schiffer
Editor-in-Chief
Chemical Reviews
Sun CQ/EEE
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Email: shs-office@chemrev.acs.org
Fax: (202) 513-8860
Phone: (814) 935-6913
Referee
Comprehensiveness
Clarity
Impact
Technical quality
English useage
A
B1(03/03) B2(3/06)
Good
Good
Good
Good
Fair
Good
Good
Good
Good
Good
Good
Good
Good
Excellent
A: The manuscript gives a comprehensive review of different experimental skills (STM/S,
PES, AES, etc.) to study the coordination bonds and energetic electrons in various materials
(metals, alloys, semiconductor, nanostructures, etc.). The zone-resolved photoelectron
spectroscopy (ZPS) technique was emphasized and proved to be a useful method in
analyzing surface status, bond coordination, point defects, etc. I find that the manuscript is of
broad interest to researchers in the field. It shall be considered for publication in Chem. Rev.
after some revisions addressing the following points.
B: This review provides a detailed review on many atomic scale structural aspects of
clusters and coordination materials. While the authors are certainly very knowledgeable in
this research field, the review lacks a coherent theme or a clear focus in terms of the
structure-property correlation.
In the very beginning, it appears the review will attempt to discuss the correlation of the
structures with catalytic properties. However, after reading the review, the word of catalytic
or catalyst is merely a general mention. There is no specific structural-catalytic correlation,
which is reflected in many of the discussions. For example, in Page 85, it states: “CuPd is
more active for the CO and alkene oxidation, CO, NO, benzene, toluene, and 1,3-butadiene
hydrogenation and ethanol decomposition [260]”. However there is no actual specific to
substantiate this statement. By looking into the reference of 260, nothing about these
catalytic reactions is mentioned. There are many similar statements like this throughout this
review.
Proposal:
Referee
Timeliness
Comprehensiveness
Probable clarity
Probable impact
Author qualification
Recommendation
A(20/06)
B(20/07)
Excellent
C(03/10)
C(20/06)
Good
Excellent
Good
C(20/07)
Good
Good
Excellent
Suitable without change
Fair
Possibly suitable with
major changes
A: Keep the good work.
B: Regular structures of solids are analysed routinely in terms of coordination numbers,
bond lengths, angles and energies. This is standard content of current text books and
Sun CQ/EEE
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teaching in undergraduate courses. But this is not what Sun et al. propose to cover in their
review. Rather, they want to address the local changes of these properties in the presence
of irregularities such as heteroatoms, defects, near the surface and near corners, edges and
kinks. This is the case of “ill-coordination” and under-coordination. It is important to
understand these effects in nanomaterials where the fraction of undercoordinated atoms
becomes large because of the high dispersion, and it is essential in catalysis. The challenge
is first an experimental one. The data in the review will be from modern spatially resolved Xray spectroscopy techniques and from STM. Information was collected for many elements
and structures and then analysed systematically. Quantitative, although empirical, relations
are derived which often remind of similar relations known for the bulk, but here they relate to
the situation around imperfections or in general around “ill-coordinated” atoms.
Since the review aims at understanding and even engineering the nanomaterial world
including heterogeneous catalysts it will be extremely useful and of broad interest to
today’s chemistry community. It has a tutorial, perhaps even a visionary touch as it
introduces important concepts. The table of content reveals a rigid structure of the review.
It is worth mentioning that the responsible author has an excellent record of publications on
this subject in international journals of high reputation, which documents that the work is
generally judged as sound and useful. I therefore recommend that this review should be
written, and I am looking forward to see it coming out. Having said this I also note that the
texts are often somewhat heavy to read because they are packed with technical terms and
acronyms (but the language is always precise). The suggested title may serve as an
example: “Coordination-resolved scoping of local bond relaxation and electron binding
energy-shift”. Would the following title not perhaps be more accessible and attract readers
better: “Dependence of bond lengths and electron binding energy on local coordination in
perturbed and nanosized materials”?
C3:The authors try to tackle wide range of rather complicated problems with relatively simple
empirical approach. Even if I am not sure that the approach put forward by the authors will
become widely accepted and adopted by catalytic and spectroscopic communities I guess it
would be useful to write this review.
Taking into account the proposed length of this review the authors should consider also the
possibility to publish it as a book.
C2: With regard to the previous papers of the author and his collaborators on the same topic
I would suggest to shorten the present manuscript. Taking into account the fact that the
author came with empirical BOLS approach for the first time some 7 years ago and
considering the significant possibilities of this method declared by the author it would be
desirable to mention in the paper also the results and experience obtained with this
technique by other authors in the world. The ZPS method consisting of calculation of the
difference spectra from the angle resolved spectra has many limitations for real samples
which decreases considerably its applicability. For chemisorption and catalysis the
configuration of adsorption sites is usually important. Furthermore, as shown e.g. by Gabor
Somorjai and his collaborators the surface structure undergoes reconstruction in the atomic
scale during chemisorption and during catalytic reaction. It is not clear in this context how
BOLS-NEP-TB approach can be used to provide guidelines for design of catalysts for
particular processes as declared by the author.
C1: The topic dealt with in this contribution is undoubtedly interesting for people working in
the field of surface and material science. If published the problems and limitations of the
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described methods should also be mentioned and discussed (influence of surface
roughness, surface contamination, surface enrichment of bimetallic system by one
component, well known change of surface composition of alloys caused by adsorption and
catalytic reaction, anisotropy of photoemission caused by photoelectron diffraction, problems
with background subtraction in the case of spin-orbit split doublets,...).
Hydrogen-bond relaxation dynamics: Resolving mysteries of water ice, Coord Chem
Rev, 285, 109-165 (2015)
A: In this article, authors discuss broad research area on water based on the intermolecular
interactions between two water molecules. The article is quite long and its coverage is
broad. It was also conducible for me to read such a massive review article, while I found
some unconvincing descriptions.
B: This manuscript is a review of the latest works related with the atomic structures of ice,
water and chemical-physical properties related including the explanation of some anomalies
of water-ice behaviour. It is an exhaustive review with almost 400 references with interesting
results and concepts, like the water-skin, Mpemba Paradox and thermodynamics
explanations. However, it looks like that has been written too fast, even after the revision,
because this manuscript is a revision version, and some improvements should be applied. I
think that this manuscript could be published only after a carefully major revision addressing
the following comments.
Chem Rev
Dear Prof. Sun:
Of the large number of proposals for review articles that Chemical Reviews receives we are
only able to accept some. Based on the lukewarm response of the reviewers, I regret to say
that the particular proposal that you submitted is not among them and hope that some
future proposal on a different subject will fare better. Thank you for considering our
journal for the publication of your work.
Sincerely,
Prof. Josef Michl
Editor-In-Chief
Ref
Author’s contribution
Timeliness of subject
Comprehensiveness
Probable clarity
Probable impact
Author qualification
Interest in reviewing
final manuscript
A
Significant
Excellent
Excellent
Good
Excellent
Excellent
B
Significant
Fair
Cannot project
poor
poor
Good
None
A: Recommendation: Suitable with minor changes.
I would agree that there is scope for such a review, and the outline appears reasonably
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comprehensive. Other recent reviews may have some relevance but appear to have a
different emphasis. E.g. George Malenkov 2009 “Liquid water and ices: understanding the
structure and physical properties” J. Phys.: Condens. Matter 21 283101 doi:10.1088/09538984/21/28/283101
Prof Sun’s forays into water ice studies are relatively recent but he has transferred expertise
and tools from materials science to make a significant contribution already, developing
models that are consistent with much experimental data.
---------------------------------------------------B: Not suitable for Chemical Reviews.
I cannot recommend this review proposal for development into a chemical reviewers articles
for the following reasons:
1) This proposed review would deal with an area to which the authors have made
significant contributions but that it is, in itself, of low impact for the broad chemical
physics and, even, the water research community.
2) The topics proposed in this review seem to heavily overalp with the work that these
authors have been publishing in the last couple of years (note that the references of
"relevant work" listed with this proposal are all 2012 to 2013). That by itself would not an
issue, but it is my impression that it constitutes a very narrow focus for a Chemical Reviews
article. I do not expect such an article will have a large readership.
3) I read several of the relevant papers listed by the authors on the topics of this proposal to
assess the probable clarity of the proposed review. I found the clarity of the papers
wanting in four respects:
i) most discussion in the papers is self-referential, to other papers by the principal author
without much focus on a larger picture of the problems addressed and little discussion of
overarching implications that go beyond the narrow focus of the results presented.
ii) the citation of other authors literature in these papers was somehow whimsical (e.g. some
papers were cited for arguments that were not there, or that provide results that do not relate
to the context in which they were cited)
iii) there is a lose use of terms (e.g. super solidity) that have a well-defined meaning but are
used by the authors in an -again- whimsical manner to characterize behavior that bears no
resemblance to its original definition (it should be noted that a full section of the proposed
review would be devoted to skin super solidity). When reading these papers I found in many
cases that the authors were using terms (concluding?) that did not correspond to the
evidences they presented.
iv) the grammar and the clarity of the narrative in the papers is wanting.
A Supersolid Skin Covering both water and Ice, PCCP 16 (42), 22987-22994
A: This paper addresses a very interesting topic, namely the unusual properties of the top
layers of ice and the skin surface of water. The authors claim that both surfaces are in fact
identical, based on experimental and theoretical results. The paper is very interesting, but
unfortunately its present version is too difficult to understand, both because the English is
very poor, and because the figures and tables are confusing and the captions are not
sufficiently clear. Therefore I am sorry to advice rejection in its present form.
Sun CQ/EEE
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B: I think there may be some significant results here, but the manuscript is so poorly written I
cannot tell.
Skin-resolved bond contraction, core electron entrapment, and valence charge
polarization of Ag and Cu nanoclusters, PCCP 2014. 16 8940-8948.
A: Authors analyzed bonding parameters and electronic structures of silver and copper
clusters. They compare BOLS and NEP frameworks with DFT calculations using LDA
functional and available experimental data. They claim that the shell atoms have shorter
bonds than the core atoms, due to undercoordination of these atoms. They conclude that
this effect stands behind extraordinary catalytic properties of Ag/C u nanoparticles. I would
recommend publication of this particular manuscript after considering below-listed points.
B: This work is an interesting investigation. The authors present here a predictions made on
the framework of BOLS correlation and nonbonding electron polarization (NEP) mechanism
by comparison between density functional theory calculations and experimental observations
of Ag and Cu atomic clusters. The methodology is appropriate and the results are interesting.
In my opinion the paper can be published with revision.
Potential Paths for Hydrogen-Bond Proton Symmetrization in Commpressed Ice, J
Phys Chem B 2013 117(43): 13639-45.
The authors use a combination of MD simulations, Lagrangian mechanics and experimental
Raman data to deduce a potential for the asymmetric O-H:O H-bond potential in
compressed ice. The approach seems new and worth publishing but I have a number of
comments that I would like to see addressed before recommending for publication.
Skin dominance of the dielectric-electronic-phononic-photonic attribute of nanoscaled
Si, Surf Sci Rep 2013. 68(3-4): 418-455.
A: This paper reviews, analyzes, and interprets the properties of porous Si. This includes
electronic as well as vibrational properties and how these properties may be tuned with
different compositions and treatments of the porous Si. The topic is certainly an important
one from both scientific and technological perspectives. The authors are knowledgeable
and present a great deal of information. They point out in the abstract and the Introduction
that there are many different explanations offered and one of their objective is to formulate
a unified understanding of the properties of porous Si. This is a laudable objective.
However, suitable revisions could help them to achieve this objective and could make their
presentation one that the readers of SSR could more easily follow and learn from. There
are a series of constructive comments ranging from technical content to the language
used.
The authors stress the importance of atomic coordination and bond distances in porous Si
and they describe the theoretical foundations as coming from Goldschmidt, Feibelman, and
Pauling. The concepts of coordination and bond distance are regularly used to describe the
size dependent properties of nanoparticles and there is an extensive literature, especially
for metal nanoparticles. As far as I can tell, this literature is not cited and the properties of
metal nanoparticles are not related to the properties of porous Si. It would be useful to cite
some of this literature, perhaps from the work of the Freund, Goodman, and Campbell
Sun CQ/EEE
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groups. Depending on its relevance, it might be worthwhile to make comparisons between
the effects of coordination and lattice strain in metal nanoparticles and in porous Si.
A closely related matter concerns the presentation of the detailed equations throughout the
text. Non-specialists in the properties of Si materials will have difficulty following them and,
even specialists may have some difficulties. Either more time should be spent explaining
the definitions and physical significance of the various terms in the equations or fewer
equations should be used and a greater emphasis on physical significance of these fewer
equations should be made. It is not clear to what extent the equations are specialized to Si
materials or whether they are generally applicable to nanoparticles. Some of the later
equations are clearly applicable only to Si while some of the earlier equations seem to
apply generally to Si as well as to other elements. It would be very useful to explicitly
identify which relationships are general and which are specific. It would also be useful to
briefly describe the key approximations used to derive the relationships. Such descriptions
will help the reader understand the limitations of the relationships.
The introduction gives for several of the phenomena of interest lists of competing
explanations of the physical and chemical origins of the observed values. For example on
page 5, 12 models are listed that have been used to describe and explain the
photoluminescence shifts and it is stated that: “Each model demonstrates its advantages.” It
would be of great help to the readers if these advantages and disadvantages were
explained either in the Introduction or in an appropriate section of the body of the paper. In
a similar way, it is noted in the Introduction that initial state, final state, or two other
mechanisms may be responsible for the shifts of core level binding energies. But there is no
further discussion of initial or final state effects in the body of the paper.
The discussion of the origins and meaning of the Si 2p BE shifts should be revised and
strengthened. The distinction of initial state and final state effects needs to be discussed
and used to support conclusions. There is good evidence that hybridization, an important
aspect of the bonding of Si, contributes to XPS shifts and this should be discussed. The
work of Bagus and his collaborators could be discussed in the context of the Si 2p XPS
shifts. A few specific points. The correlation of BE shifts with particle size was originally
proposed by Wertheim and his collaborators for metal nanoparticles and they present it as
entirely a final state effect. This should be pointed out in the paper. Further, it could be
appropriate to mention the Wagner Auger Parameter as a way to experimentally separate
initial and final state effects. It is difficult to measure particle size and the range of particle
sizes. Thus, there may be uncertainties in the plots of XPS energies against particle size.
The authors state on page 17 that energy band theory has been used to determine the XPS
core level shifts. While it is true that band structure theory can and has been used to
explain XPS spectra, this application requires extensions to band theory that are not
needed for the more usual applications to the determination of lattice constants and
cohesive energies. These would include some discussion of localization of the core level
and the separation of initial and final state effects. Fig 2a shows a shift of the Si 2p binding
energy from the smallest particle to bulk of ~7 eV. This is a very large XPS shift. For metal
nanoparticles the shift is ~1 eV. The large shift for Si deserves some comment to put it into
the context of other size dependent XPS shifts.
It is clear that the authors are not native English speakers. There are a few places where
the construction is awkward and, sometimes, difficult to follow. It would be helpful if
Sun CQ/EEE
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someone proficient in English go over the paper with the authors.
Overall this is a nice paper. The constructive suggestions made above should help it reach
a broader audience.
B: Understanding the properties of nanostructures is very important both for their synthesis
and for developing new applications as well as establishing their fundamental properties.
Objects in nanometer scale made from a few tens and hundreds of atoms do not behave in
the same way as bigger, macroscopic objects. Hence, any investigation that provides an
insight to these novel properties is critical, actually, these might provide an economical
alternative to expensive, costly and time consuming, experimental efforts. Therefore, any
modeling study of nanostructures is very beneficial.
In this manuscript, size dependence of several physical quantities from dielectric, electronic,
phonic and photonic properties of porous silicon are discussed and modeled in terms of
nature of their bonds (surface versus bulk) and coordination. Main aim of the manuscript is
provide this simple understanding so one can manipulate p-Si or nanostructured Si in
general for tunable properties. Specifically, the size dependence of the Raman shift, band
gap, photon luminescence (PL) and photon absorption (PA) energies, core level shift, stokes
shift, dielectric susceptibility and imaginary dielectric constant are described by using local
bond average approach, and the correlation and general trend between them are introduced.
So, with correlation, one can get information about any of these physical properties once
having the detailed knowledge of one of them. Since, the bonds of surface region (i.e skin,
couple of layers from the surface) are critically modified; the mentioned physical properties
are influenced by these surface bonds like dangling bonds. Therefore, surface passivation
with O and F or metallization with Al, Cu and Ti are discussed in detail since these
processes affect surface bonds so the mentioned properties.
Size dependence of several physical properties of different Si nanostructures and their
possible explanation are reviewed from the literature in the first part of the manuscript. Then,
the authors confined their discussion on p-Si, and reviewed and discussed the above
mentioned physical properties mostly from their own work.
However, there are some issues needs to address: It would be very nice to have a careful
“language” and English check of the manuscript. Second, most of the figures are reproduced
from the literature. For example, Figure 1 from Ref 21, Figure 2 from ref 56, Figure 3 from
Ref 51 and these are cited in the manuscript. However, it would be much clear to state they
are from the corresponding references instead of just citing them.
In conclusion, I would recommend publishing this manuscript on Surface Science Reports
after considering the point raised above.
Density and phonon-stiffness anomalies of water and ice in the full temperature range,
JPCL, 2013. 4: 3238-3244.
Referee
Urgency
Significance
Novelty
Sun CQ/EEE
A
High
B
Moderate
Top 10%
High
C
Moderate
Moderate
Moderate
8
Presentation
Broad interest
Moderate
Yes
Low
A: The paper has some novel results likely to be of considerable interest – combined
spectral observations with MD simulations. It should be publishable, but there are several
aspects to fix up first.
B: This paper presents a combined molecular dynamics simulations with Raman
spectroscopy experiments to study the effects of cooling on the density of liquid water and
ice. It is an interesting paper which presents a new interpretation of the effects of cooling on
water. I have a few suggestions.
Density, Elasticity, and Stability Anomalies of Water Molecules with Fewer than Four
Neighbors. J Phys Chem Lett, 2013. 4: 2565-2570.
Referee
A
B
Urgency
Moderate
Significance
Moderate
Novelty
Moderate
Presentation Moderate
Low
Broad interest
Yes
A: This paper uses DFT electronic structure methods to examine how water-water distances
and phonon frequencies change with different coordination numbers for water clusters.The
paper could be strengthened by addressing the following points:
1) GFP is never defined
2) "skin" should be replaced with "surface" or "interface" throughout the manuscript
3) On page 9, the itemized point i) mentions that the effects they find dictate the unusual
behavior of water. What behavior of water are they talking about and how do those effects
(contraction and elongation of hydrogen bonds with different coordination number) lead to
those effects? While this may have been discussed in the paper it would be worth
summarizing those results more clearly here.
B: I have read with care the manuscript by Sun and colleagues and, even though it is
interesting, I think that it cannot be accepted for publication in The Journal of Physical
Chemistry Letters in its present form for the reasons detailed below.
The authors have tried to provide computational-theoretical explanations-rationalizations for
the anomalous behaviour of thin layers of water and of small water clusters by performing
DFT calculations. They have investigated several small clusters and the main finding is a
shortening of the covalent H-O bond and a lengthening of the non-covalent part of the
hydrogen bond O...H-O. The authors in the introduction of the manuscript anticipate this
result on the basis of simple considerations grounded on the contraction of atomic radii of
under-coordinated atoms pointed out, long time ago, by Goldschmidt and Pauling, and on
the electrostatic repulsion between the electrons on the two oxygen atoms.
Sun and colleagues have emphasized that their results are in line with some experimental
findings, but I think that it would be more important to show that their results for small
Sun CQ/EEE
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clusters are in agreement with those of other authors. For instance, Saykally and co-workers
have extensively characterized both experimentally and theoretically clusters identical or
very similar to those considered by Sun and colleagues; the latter have cited some of these
analyses, see references 9 and 10 of the manuscript, but have not discussed their own
results in comparison to those by Saykally.
The manuscript is not simple to judge because it is not clear what is original and new. For
instance, Sun and colleagues report Eq. (1) that should come from a different work,
comment on its meaning, and then write that such relationship should not work well for water
because “an isolation of each water molecules by the surrounding four lone pairs
differentiates water’s response to the under-coordination effect from other materials”. This
statement is very strange.
Similarly the authors write “the shortening of the H-O bond raises the density of the core and
bonding electrons in the under-coordinated molecules, which in turn polarizes the
nonbonding electron lone pairs on oxygen”. The meaning of this sentence is not transparent:
the shortening of the H-O bond should be the consequence of the behavior of electrons and
not the cause of their behavior.
Raman spectroscopic determination of the length, energy, Debye temperature, and
compressibility of the C-C bond in carbon allotropes，Chem Phys Lett 575, 21, 86–90
A: They applied the bond order-length-strength (BOLS) theory to reproduce the Raman
shifts of carbon allotropes like graphene, graphite and SWCNT. The BOLS theory is a simple
elegant theory and it has been successfully employed in correlating intrinsic molecular
quantum mechanics with physical properties of the materials in many aspects. In this
manuscript the Raman shifts reproduced by BOLS theory matched the experimental data
very well, and valuable quantitative information on molecular level were obtained. In all, this
is a high quality paper.
B: This paper uses BOLS approach previously developed by one of the authors (SUN) has
been used to determine various quantities of interest of C-C bonds in carbon allotropes.
Allotropes determined include graphene, CNTs, C60, diamond, graphite. The technique
described by authors elegantly reproduces, quantitatively, various measured quantities
including bond length, energy, modes, Debye temperature, etc. I have also looked at
previous papers by authors and find it significant that BOLS is becoming a highly effective
tool. The value of the paper is that it provides an analytic solution that connects Raman shift
to identity of the bond type in these allotropes. I see no obvious weakness in the paper and
recommend its publication as is.
Hidden force resolving water-ice densities, PRL LV13469, rejected.
Hidden force stiffening undercoordinated water molecules, PRL LW13133, rejected.
A: The findings make sense to me and I recommend the papers for publication.
B: I have been asked to comment on the above manuscript and LW13133 by the same
group. The work itself is mostly OK though I have reservations about the robustness of the
computational approaches used. There appears to be new insights contained within these
Sun CQ/EEE
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papers but like past submissions the papers are extremely hard to read, encoded in flowery,
idiosyncratic and overly complicated terminology that greatly clouds the substance of the
paper. My review is the same for both works - in their current state I think they are unsuitable
for publication anywhere because they are so difficult to read. Some might view this as harsh
but I feel that the work should be as accessible as possible, indeed I think is a basic
requirement for a PRL. The title says it all '...the thermodynamic disparity of the masterslave-segmented H bond..' is barely comprehensible. I think it is in the communities interest
that the works be rewritten as simply as possible. I also think it is in the best interests of the
authors who will generate much greater impact if readers can easily understand the novel
ingredients of the work. I rarely reject papers completely unless they are patently unsuitable
but in this case I recommend rejection; until the papers are expressed more clearly I am not
prepared to mentally rewrite the papers to make them intelligible - the authors should have
done this work for me. I feel it is important that the authors work to simplify their presentation
and I would be prepared to review the works again if submitted to PRL, provided the work
has been rewritten as clearly as possible.
Size-depressed critical temperatures for the order-disorder transition of FePt, CoPt,
FePb, Cu2S, and ZnS nanostructures, Chem Phys Lett, 555 (2013) 202–205.
A: In this paper, the authors report about an analytical model of the chemically orderdisorder transition or solid-solid transition in alloyed FePt, CoPt, FePb, Cu2S, and ZnS
nanocrystals, based on the bond order-length-strength correlation, core-shell configuration,
and local bond average effect. These works try to demonstrate the role of atomic
undercoordination and the associated loss of atomic cohesive energy of atoms in the skin
region, as the driving force of size effect on transitions.
The paper presents an interesting non-atomistic point of view about the average bong lengh
effect on the order-disorder and solid-solid transition temperature Tc for the alloy and
compound nanostructures and that the reduction of Tc is dominated by the skin effect.
However, the authors explain not clearly that this effective model compared with
experimental measurements and atomistic calculations break down for smaller particles
(K<5, less than 2.5nm) due to skin dominated effect or others (please, give some
explanations).
The paper is well structured. However, the English could be improved.
Bond Order Resolved 3d5 2 and Valence Band Chemical Shifts of Ag Surfaces and
Nanoclusters, J Phys Chem A 116, 7892–7 (2012)
This paper deals with the most challenging problem of the binding energy shift of Ag
surfaces and nanoclusters on oxide substrates using the BOLS-TB based analysis with
derivatives of the binding energy of an isolated atom and the bulk shift, as well as the
correlation between the valence band and the 3d core level. The approach is novel and the
analysis is trust worthy. The paper is well organized and properly referenced. I suggest the
paper to recheck the spellings and program as I found some typos. This manuscript reports
a quality work by a reputable group, which is certainly useful, and therefore, I recommend
acceptance.
Sun CQ/EEE
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The hidden force opposing ice compression, Chem Sci 3, 1455-60 (2012)
A: This work brings new insight into the study of ice. I was excited to see the cutting edge
research brought to bear on ice research, which, for various reasons, is key to many fields of
science and engineering. The manuscript is well written and the novel findings are well laid
out. This work should provide new impetus to study of ice compression. The simulations of
O-H and O : H bond distances brings added certainty to the claims. I especially like the
approach taken by the paper, whereby the expectations and hypothesis are compared later
in the manuscript.
B1: This paper is focused on the nature and origin of the physical anomalies of water ice
upon compression up to 60GPa. The authors segmented the representative H-bond into
longer-and-weaker intermolecular virtual-bond and the shorter-and-stronger intramolecular
real-bond firstly, and proposed a hypothesis that the resultant force of the compression fp,
the Coulomb repulsion fq, and the recovery of electron-pair dislocation fr determines the
lengths and strengths of the real-bond and virtual-bond segment. The MD-DFT calculations
and experimental data are used to verify their hypothesis. The novel concept proposed in
this paper that “Coulomb repulsion between the unevenly-bonded electron lone pair and the
bonding pair of the H-bond forms the soul dictating the anomalies of ice upon compression”
is helpful to understand further the nature of H-bond and physical anomalies of water ice
under compression.
Zone-selective photoelectronic measurements of the local bonding and electronic
dynamics associated with the monolayer skin and point defects of graphite, RSC Adv
2, 2377-83 (2012)
This is an excellent paper on the role of defects (vacancies) in the bonding and dynamics on
graphite. Additionally, the authors show the ZPS is a valuable tool for such studies. Their
conclusion on polarization of unpaired dangling bond electrons in graphite has implications
beyond graphite. One minor suggestions to the authors is to abbreviate the title.
Nice work, recommend its publication.
Mesoscopic superelasticity, superplasticity, and super rigidity, Sci China-Phys Mech
Astron 55(6): 963–979 (2012)
The paper provides not only a comprehensive review but also convincible explanation of the
superelasticity, the superplasticity, and the superrigidity of materials demonstrated at the
small scale, with mechanism that remains as long puzzle. Based on the bond-order-lengthstrength theory and its extension to the domains of pressure and temperature, the author
has correlated, formulated and quantified these fascinating behaviors, which has
discriminated the intrinsic physical parameters of bond relaxation, binding energy density
and atomic cohesive energy from the extrinsic parameters of pressure and temperature. The
theory reveals the correlation among the mechanical properties of nanosolids such as elastic
modulus, yield strength, etc., and the thermodynamic properties, e.g., atomic cohesive
energy from the atomic coordination view, the temperature and the pressure effects on the
mechanical characterization are also considered by demonstrating the interaction between
the extrinsic factors and the intrinsic binding physics of nanosolids. The topic is very
interesting, and the work contributing to the understanding the meso/nano-scopic mechanics
Sun CQ/EEE
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and clarifies the confusions in the related fields.
ZnO meso-mechano-thermo Physical Chemistry, Chem Rev 112, 2833-52 (2012)
A: From the novel and unique perspectives of the bond order-length-strength (BOLS) and
nonbonding electron polarization (NEP), this manuscript described an elegant theoretical
work to correlate and formulate the physical properties, as well as to quantify the
corresponding quantities of ZnO, i.e., the elasticity, band gap, phonon frequency, thermal
stability, the diluted magnetism hydrophobicity, and enhanced catalytic ability. Using the
local-bond-averaging (LBA) approach, the changes in the bond order, length and strength of
ZnO structures would cause consequent modifications of the physical properties. The
authors successfully established a new theoretical model in describing and quantifying the
size, shape, temperature and pressure effects on a variety of physical quantities of ZnO, and
providing an insight into physical mechanisms. This is a paper with high quality.
The authors did very good work and established a novel BLOS model in formulating, unifying,
clarifying, and quantifying the physical properties, as well as the size, shape, temperature
and pressure effects on ZnO nanostructures. Although there are some problems in this
manuscript listed above, this manuscript definitely deserves publication in Chemical Review
after necessary revision.
B: Publish after minor revision.
D: Publish after minor revision.
E: The authors from the perspectives of bond order-length-strength correlation and
nonbonding electron polarization, correlated the elasticity, band gap, phonon frequency
thermal stability and the diluted magnetism hydrophobicity, and enhanced catalytic ability of
ZnO and formulated their size, temperature and pressure dependence using the local-bond
averaging approach. The authors well summarized and analyzed the obtained results, which
are very helpful to the community. “Bond” idea is very fundamental and useful to the
multidisciplinary researchers, I believe this review article will attract general interest. I
recommend its acceptance with a minor revision.
Referee
Comprehensiveness
Clarity of Presentation
Impact
Technical Quality
English usage
A
Excellent
Good
Excellent
Excellent
Good
B
Good
Good
Good
Fair
Fair
C
-
D
Good
Good
Good
Fair
Good
E
Good
Good
Excellent
Good
Good
Editor: We are pleased to inform you that your manuscript has been accepted for
publication and sent to the Production Department. This is clearly an outstanding manuscript
and we are pleased to have the opportunity to publish it. Publication has been scheduled for
an upcoming regular issue of Chemical Reviews.
Correlation between the band gap, elastic modulus, Raman shift and melting point of
CdS, ZnS, and CdSe semiconductors and their size dependency Nanoscale 2012, 4,
1304-1307
A: This paper is devoted to an important area of nanoscience research. The modification of
Sun CQ/EEE
13
the fundamental properties of materials at the nanoscale can lead to novel phenomena and
devices. In particular, the authors provide experimental evidences supporting the validity of
the model based on the bond-order-length-strength (BOLS) correlation for II-VI
semiconducting nanostructures.
B: This paper correlates the seemingly irrelevant properties of the band gap, elasticity,
Raman shift and melting point of CdS, ZnS, and CdSe semiconductor and their size effect,
using the BOLS theory of CQ Sun, which demonstrates how importance of the crystal size
and the undercoordinated atoms. Findings show that if one knows any one of the properties,
and then he should know the rest. The work is interesting and important. The paper is well
written and referenced. I recommend accept as is.
Edge Hydrogenation Induced Spin-Filtering and Rectifying Behaviors in the Graphene
Nanoribbon Heterojunctions JPCC 115, 25072–6 (2011)
A: The authors have investigated the electronic transport properties of edge hydrogenated
zigzag-edged graphene nanoribbon heterojunctions through the nonequilibrium Green's
functions. Their results show that a perfect spin filtering with 100% spin polarization and a
rectifying behavior with a ratio larger than 105 can be realized by di-hydrogenation. These
results are quite interesting and are useful in the design of high performance spin filter and
spin rectifier. The current research clearly advances the field and is of broad interests to the
readers. I am happy to recommend the publication of this paper as is.
B: The spin related electronic transport properties of graphene nanoribbons have been the
hot topics of recent years. Based on the calculations obtained from the nonequilibrium
Green's functions and the density functional theory, the authors report perfect spin filtering
effect and large rectification observed in monohydrogen-terminated and dihydrogenterminated zigzag graphene nanoribbon heterojunctions. The underlying mechanism are
from the opposite parities of Pi (Pi*) subband in monohydrogen-terminated and dihydrogenterminated zigzag graphene nanoribbon, as well as the asymmetric distribution of
transmission spectrum. The calculation results are reliable and the discussions are
reasonable. The work is interesting and will be helpful for experiment in the design of high
performance spintronics devices. I recommend the manuscript accepted after some
necessary mini revisions.
Raman determination of the length, strength, compressibility, elasticity, Debye temperature
and force constant of the C-C bond in graphene. Nanoscale 4, 502-10 (2012)
A: The manuscript elucidates the underlying quantum mechanics of Raman shifts of
graphene in response to the stimuli. Based on my experience in theoretical study on matters,
the BOLS theory originally developed by Sun et al, is an elegant and effective method in
exploring the origins of diverse properties of nanomaterials at atomic level. In this paper the
authors incorporated the variable parameters into the form of vibration frequency shift and
generated the forms of frequency shift for each variable, which correlates the change of the
stimuli with the Raman shift of graphene. Based on the BOLS correlation and experimental
Raman database, the authors derived general expressions of atomic coordination, strain,
temperature and pressure dependent Raman shifts of graphene. As results, BOLS
reproduction of the Raman shifts dependence on each variable matches well with the
experimental data. Therefore the authors successfully illuminated the mechanism of Raman
Sun CQ/EEE
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shifts of graphene in relation to the bond length and energy in response to the stimuli. The
calculated parameters are valuable experimental references.
B: Authors of this presentation attempt to deal with the vibration with the change of pressure,
temperature, strain and the number-of-layer of graphene. They extended their BOLS theory
to establish the correlation between the vibration frequency and the bonding parameters
such as the bond number, length, and strength. They incorporated the external excitations to
the bond length and bond energy, and eventually reproduce the measured phonon
frequency shifts. The paper is well written and properly referenced. The subject is quite
interesting and useful.
Band gap modulation of the IV, III-V, and II-VI semiconductors by controlling the size
and temperature, J Phys Chem C 115, 23338–43 (2011)
A: Using the bond-order-length-strength correlation mechanism and the local-bondaveraging approach beyond the tunability remaining puzzling Chen et al. have studied the
size, shape and temperature effects on the band gap modulation of elemental and
compound semiconductors, such as Si, Ge, GaN, AlN, ZnO, ZnSe, and ZnS nanostructures
(nanodots and nanowires). The authors have shown that the size-tunability originates from
the skin-depth local bond relaxation and the associated quantum entrapment of binding
energy. The temperature dependence of the band gap of semiconductor arises from bond
expansion and bond weakening, showing the opposite trends to that induced by reducing
solid size. There is a good qualitative agreement with the experimental data.
B: This manuscript reports interesting results regarding theoretical modeling of the effect of
size and temperature on the measured bandgap of nano-size semiconductors. However, it
suffers from clearly putting its results within the context of existing models.
Number-of-layer discriminated graphene phonon softening and stiffening, Appl Phys
Lett, 99, 163109 (2011)
This is a nice paper that explains and quantifies the role of number of layers (n) on the
Raman shifts in graphene. The authors use their BOLS and LBA approaches to this
problem. It is clear that author's BOLS is a useful technique that can be applied a number of
currently relevant topics.
Overall an excellent paper and recommend publications in APL.
Frequency response of graphene phonons to heating and compression, Appl Phys
Lett, 99, 133108 (2011)
This is an interesting study, which reports new data for graphene Raman response under
compression and provides useful information for graphene such as bond length change, etc.
These results should be published.
Controlling the Band Gap of ZnO by Programmable Annealing, J Phys Chem C 115,
20487–20490 (2011)
Sun CQ/EEE
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A: This paper represents a significant new contribution and should be published as is.
B: This paper is publishable subject to minor revisions noted. Further review is not needed.
In this MS, the authors discuss the controlled band gap of ZnO by annealing technique. The
experimental results and theoretical calculation are reasonable in the observations of
photoabsorption (PA) and photoluminescence (PL) measurements.
Discriminative generation and hydrogen modulation of the Dirac-Fermi polarons at
graphene edges and atomic vacancies, Carbon 49, 3615-21 (2011)
A: This manuscript discusses the roles of edge geometry, defects, and hydrogenation on
existence and absence of modified Dirac Fermion as well as magnetic moment by
performing the modeled tight-binding and first-principles calculation. Finally, the proposed
electronic structure is studied by photoemission spectroscopy. I believe this manuscript
contain new scientific contents and will stimulate further research of graphene, thus I'm
pleased to recommend accept this manuscript for publication to the CARBON.
B: This manuscript investigated the appearance/quenching of magnetism dependent upon
different defective geometries in graphene nanoribbons by means of tight-binding and firstprinciples calculations in combination with the further experimental verification. The results
obtained are solid, and are well organized. The paper is original with an emphasis on
graphene-based materials, and thus a positive contribution to the field.
Atomic Scale Purification of Re Surface Kink States with and without Oxygen
Chemisorption, J. Phys. Chem. C 2011, 115, 7450–7455
A: The paper presents results from analysis of photoelectron spectroscopy data for
Re(0001) and Re(12-31) surfaces. The authors argue that by taking difference between
photoelectron spectra new information about energy states originating from
undercoordinated and/or chemisorbed atoms (e.g. oxygen) can be revealed. In general, the
approach the authors put forward makes sense. However, from what the authors present in
the paper, it is not clear to me how much the new information coming from difference
photoelectron spectra is unique, i.e. not influenced by experimental/data processing artifacts.
The authors brush off all technical details of the spectra decomposition, normalization,
difference taking protocol etc leaving the readers wonder how this "differential spectra
procedure" works in reality, how robust it is against data noise and/or wrong
assumptions/energy level assignment. I would strongly suggest the authors provide more
technical details about their approach and give the readers some guidance how it should be
applied so that good/unique results are obtained. Otherwise the paper will remain what is
now: a quite convoluted description of some experimental data processing approach that
nobody else but the authors could understand and undertake well.
B: This paper is publishable subject to minor revisions noted. Further review is not needed.
XPS revelation of W edges as a potential donor-type catalyst, PCCP, 13: 12640-12645
(2011).
Sun CQ/EEE
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A:The authors present a very thorough and technical study aiming at a better interpretation
of W 4f XPS spectra from several flat and stepped W single crystal surfaces. Based on the
analysis of the spectra the authors arrive at the conclusion that the edge W atoms are
electronegative with respect to the bulk atoms and could therefore act as n-type catalysts.
The manuscript describes excellent work and there is very little detail that would prompt
criticism.
B: The paper describes a specialized methodology for deconvolution of XPS spectra. The
key result is that this methodology demonstrates a similarity in XPS profile of W atoms and
e.g. noble metal particles (Rh adatoms). Based on the previously mentioned publications, I
am convinced that the proposed XPS methodology is of high quality, but simply not suited to
the EES journal and meant for XPS specialists.
Correlation and size dependence of the elastic modulus and the melting point of Au
and Ag at the nanoscale, J Appl. Phys. 109, 074319 (2011)
A: This paper represents a significant new contribution and should be published as is. In this
work, the authors report the size dependence of the elastic modulus and melting
temperature of Ag nanostructures. The underlying mechanism behind the elasticity
enhancement and thermal stability depression is clarified on the basis of the bond orderlength-strength correlation. This topic is interesting and it provides substantial and important
information for the understanding of size effects on physicochemical properties on the
nanometer scale.
B: In this paper the authors present a theoretical investigation of the simultaneous surface
stiffening and surface melting of silver nanoparticle, based on established methodologies. In
general, the paper is well organized, but it contains significant textual redundancy. It would
certainly help readers if the authors revised the paper to remove the repetitive phrases, and
make the explanations more succinct.
C: (Chinese paper online) Ag 纳米结构在催化、照相、生物学和信息存储以及单分子探测的
表面增强拉曼光谱等方面有广泛的应用，但是其性能取决于其弹性模量以及热稳定性。为了纠
正以往模型对弹性模量和热稳定性的概念理解，本文作者引入了单位体积内能量增益和表面分
立原子的结合内聚能剩余两个概念来解释Ag纳米结构与其弹性模量的增加以及热稳定性降低
之间的关系，文章理论分析深入，模型建立合理，分析结果正确。
Underneath the fascinations of carbon nanotubes and graphene nanoribbons, Energy
Environ Sci, 2011, 4, 627-655.
A: Through a combination of the DFT, the BOLS-TB calculation and some experimental
observation, the authors demonstrated the insight into the fascinations of graphene
nanoribbons. This paper includes abundant valuable information such as the bond and
nonbond formation, dissociation, relaxation and vibration, and the associated energetic and
dynamics of charge repopulation, polarization, densification, and localization. Although there
have been many theoretical papers studying the edge bonding condition of graphene
nanoribbons, it is important in understanding the mechanism of graphene properties and
Sun CQ/EEE
17
may be published in EES.
B: This manuscript dealt with the underneath the fascinations of carbon nanotubes and
grapheme nanoribbons. Basically it illustrated the principles of carbon nanotubes (CNT) and
graphene nanoribbon (GNR) in depth. However, it would be better to present some more
applications on energy (Themed issue: Carbon Nanostructures for Energy), other than all
theoretical explanations. It was basically physical illustration on the nanostructure of CNTs
and GNRs. It is recommended to be published in ENERGY & ENVIRONMENTAL SCIENCE.
Layer and orientation resolved structural relaxation and quantum entrapment of
Beryllium surfaces, PCCP 12, 12753 – 59(2010).
A: The authors showed that a combination of the theories of tight binding and BOLS
correlation and XPS gives useful information concerning the surface of nanomaterials.
B: The authors have developed a novel and very useful approach for the quantitative
extraction of undercoordination information from photoemission data. This information can
be quantitatively related to many physical and chemical properties of imperfect surfaces.
Imperfect surfaces containing adatoms and various types of lower dimensional defects are
usually very chemically active, and thus are frequently used as catalysts. Therefore, this
approach should be very useful for establishing structure property relationships for various
solid phase catalysts.
Dominance of Broken Bonds and Nonbonding Electrons at the Atomic and Nanoscale
(Invited), Nanoscale 2, 1930-61 (2010)
A: This article written by Sun features an important yet often overlooked issue that
dominates the performance of materials in many respects at the atomic and the nanometer
scales. The broken bonds and the nonbonding electrons and their combinations exist
everywhere and they play indeed important roles in the performance of low-D materials such
as catalytic enhancement, high-Tc superconductivity, biotechnological molecular
modification and drug design. However, they are hard to describe using available methods.
As shown in this paper, understanding these events and finding means to make them of use
have been a big question. This paper is inspiring with a new way of thinking for such
purpose. It is of merit of publication.
B: I find the review extensive, well documented and discussed. The manuscript is worth
publishing.
Graphene nanoribbon band-gap expansion: Broken-bond-induced edge strain and quantum
trap depression, Nanoscale 2, 2160-63 (2010)
A: The authors proposed an edge-modified tight-binding (TB) model to explain the energetic
origin of the width-dependent band gap (EG) expansion of the bare armchaired and the bare
reconstructed zigzag-edged graphene GNRs. However, bare GNRs are very unstable.
Instead, GNRs are usually passivated. In this case, the bond length between edge carbon
atoms is rather close to the carbon-carbon bond length in 2D graphene. The authors should
also develop an edge-modified tight-binding (TB) model for the passivated GNRs and
Sun CQ/EEE
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discuss the band gap expansion.
B: After a comprehensive introduction of the background of the band gap expansion of
graphene nanoribbon (GNR) as a function of GNR width, the authors pointed out , and it is
true, that the physical origin has yet been clear for this observation although there has been
so many publications based on DFT and TB calculations. As such, they developed an
algorithm by encoding the tight-binding approximation and the theory of BOLS (developed by
the main author) theory to reproduce the width trend of band gap change. Consistency
between their calculation results and reports by others they suggest that the bandgap
expansion arises from the edge strain and quantum trap depression that enhances the
overlap integral near the edge and thus clarified the physical origin. Their consideration of
the BOLS and the derived lattice strain and quantum trap depression are also evidence by
their previous papers and one paper published in Science [C.O. Girit, et al, Science, 2009.
323: 1705]. The paper is well written and properly referenced.
Nonbonding electrons do matter greatly Chinese paper online
A: 本文从微观角度研究了常被忽视的非键合态电子的作用，通过许多实例揭示了非键合态电
子的存在及其关联的能量学支配着低维功能材料充满奥妙的宏观行为。此论文选题新颖，内容
详实，文字流畅，数据可靠，结论正确。它能激起读者对非键合态电子的兴趣，提醒人们要透
过微观电子键合与非键合的形成、离解、驰豫、振动及其关联的电子迁移、极化、局域化、致
密化的能量学和动力学这些本质解释材料的宏观性质。
B: 此文章给人们带来耳目一新。
Purified Rhodium edge states: Quantum trap depression and the unpaired s-electron
polarization, PCCP 12, 12494 – 98 (2010).
A: The paper describes an X-ray photoelectron spectroscopy study of undercoordinated
rhodium atoms. Undercoordinated atoms are of significant interest since they play an
important role in many chemical processes. The work extends a recent study published in
PCCP [12 pg 2177 yr 2010] and there are probably sufficient new findings in the current
work to merit publication.
B: The authors address the interesting properties of undercoordinated atoms in surfaces
with artificial defects. They analyze X-ray photoelectron differential spectra (XPDS) in the
particular case of rhodium (Rh) and derive the electronic density-of-states (DOS). They find
extra energetic states in the Rh-3d5/2 band; the core level shifts are signatures of shorter
and stronger bonds between the undercoordinated atoms. The experimental works seems to
be decent. One can follow up the conclusions.
Interface quantum trap depression and charge polarization in the CuPd and AgPd
bimetallic alloy catalysts, PCCP 2010. 12: 3131 - 3135.
A: This is an exciting paper that reports on X-ray photoelectron spectroscopy (XPS) analysis
of the valence and core orbital energy levels in CuPd and AgPd alloys. Significantly, the
outcomes show that the valence and core electron energy levels in CuPd alloys are shifted
Sun CQ/EEE
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to higher energies, while AgPd shows the reverse trend. In the context of the known
behavior of these alloys, this trend is internally consistent with CuPd acting as a charge
acceptor due to quantum trapping, while AgPd is associated with donor or charge
polarization behavior.
In this work, the electron spectroscopy evidence is very convincing. In fact, this data is
unequivocal in the context of the binding energy shifts and the corresponding interpretation
of these shifts. The paper makes an interesting and significant contribution to the field.
Since these materials are utilized in catalysis and their behavior is vastly different, these
important new insights about these materials should intensify efforts to harness these
materials in catalytic applications.
B: I believe this is a very important paper which should be published in PCCP. The behavior
of alloys of this type can be very confusing and there are a number of contradictory reports
in the literature on the subject – for instance, the nature of charge transfer in the system. I
think the paper goes a long way to helping the reader understand these systems and their
sometimes apparently anomalous behavior.
Mechanically Stiffened and Thermally Softened Raman Modes of ZnO Crystal. J. Phys.
Chem. B, 2010. 114: 1648-1651.
A: This paper represents a significant new contribution and should be published as is.
The paper presents the effects of pressure and temperature on the Raman modes of ZnO
crystal. The paper is very interesting and well written. The conclusions are supported by the
data. Therefore, I strongly recommend publication of this manuscript.
B: This paper is publishable subject to minor revisions noted. Further review is not needed.
ZnO is a useful optoelectronic material and a large number of investigations have been paid
to its structure and optical and electronic properties. Raman scattering has been proved to
be a useful tool for studying the electron-phonon interaction which involves many new
effects in the promising material. In the current manuscript the authors theoretically revealed
the stiffening by pressure and softening by heating of the Raman active Modes in ZnO
crystal by using their developed BOLS correlation theory plus the LBA approach. Their
calculation results are consistent very well with the reported experimental data. Therefore,
this manuscript is worthy of publication. It will be better if the authors could compare their
calculation results with those from the corresponding nanoscale ZnO crystals. The currently
more measurements are carried out on the nanostructured ZnO materials. If the authors
could use their theory to explain some experimental results from nanomaterials, this will
largely help understand the behavior of electrons and phonons and promote the
development in device fabrications.
Local structure relaxation, quantum trap depression, and valence charge polarization
induced by the shorter-and-stronger bonds between under-coordinated atoms in gold
nanostructures. Nanoscale, 2010. 2, 412-417.
A: Nanomaterials attract lots of attentions due to their special optical, catalytic etc properties
in applications. These properties are from special structures, especially (near) surface
Sun CQ/EEE
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structure. In this contribution, the authors combined BOLS theory (mainly developed by C.Q.
Sun, one of the present authors) and DFT calculation to investigate the electronic and the
atomic structures near surface. Some important physical phenomena, such as skin-depth
bond contraction, core level shift etc, have been studied, and the results are consistent with
available experimental data. This work is important to deepen one’s understanding of the
structure-properties relation of nanomaterials.
B: The unusual behavior of nanostructures is indeed fascinating, which has stimulated
extensive research interest. Compared with the tremendous efforts in nanostructure
synthesis, characterization and functionalization for applications, the fundamental
understanding is rather weak, in particular, the issue of the correlation between the local
crystal structure, electronic configuration and the binding energy remains unsolved.
In the present manuscript, the authors reported their DFT calculation results of the lattice
strain, charge transfer in real space from the inner to the outer atomic shells, valence charge
polarization from lower to higher binding energies of two kinds of well-defined gold
nanoclusters with many useful findings. The authors have also used the experimental results
mainly from the literature to support for their findings. They explained their findings using the
BOLS theory developed by one of the authors. The consistency between DFT calculations,
experimental observations and the BOLS predictions suggests that the shorter and stronger
bonds between undercoordinated atoms create the local strain and potential quantum
trapping. Polarization of the valence charge of gold by the tightly trapped core charge takes
places.
The analysis is consistent and well-supported by the data and explanations. This work
generates new knowledge on the crystal structure relaxation, binding energy evolution and
the charge configuration of gold nanoclusters, which can be straightforwardly extended to
other low-dimensional systems. The work is novel, interesting, and comprehensive and as
such definitely warrants publication in the Nanoscale.
Orientation-resolved 3d5/2 energy shift of Rh and Pd surfaces: Anisotropy of the skindepth lattice strain and quantum trapping, PCCP, 2010. 12: 2177-2182.
In its revised form this paper is much clearer and the points raised in my comments on the
original version have been met. It will be interesting to see how widely used the BOLS
algorithm, as extolled here by the author, becomes.
Adatoms-induced Local Bond contraction, Quantum Trap Depression, and Charge
Polarization at Pt and Rh Surfaces, JPCC 113, 21889–21894 (2009)
This paper represents a significant new contribution and should be published as is.
In this paper, authors describe their analysis of Pt 4f and Rh 3d photoemission spectra taken
by Baraldi et al. and Fang et al. based on their originally developed algorithm. Their
interpretation of the “polarization state peak” observed in Rh spectra as indication of donor
catalytic behavior of Rh is interesting and important.
Sun CQ/EEE
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Coulomb repulsion at the nanometer-sized contact: a force driving
superhydrophobicity, superfluidity, superlubricity and supersolidity, J Phys Chem
C113, 20009-19（2009）
A: This paper is probably publishable, but should be reviewed again in revised form before it
is accepted. Contacts between nanometer-sized solid-solid or liquid-solid interfaces are
characterized by frictionless motion, producing superhydrophobicity, superfluidity,
superlubricity and supersolidity. Even though these 4S phenomena are very interesting, no
general explanation for their occurrence exists. The purpose of the manuscript by Chang
Sun and colleagues is to try to provide such an explanation.
The basic idea is simple: (1) the skin region of a nanometer-sized interface is full of
atomic-level defects and the atoms in such a skin have a number of nearest-neighbors
smaller than in the bulk; (2) this should cause a shortening and strengthening of the existing
bonds with a consequent increase in energy and charge density in the skin region; (3) if this
is true for all nanometer-sized interfaces, the charge density increase would imply that all the
skin regions are negatively charged and so they repel each other for simple electrostatic
reasons, producing the frictionless motion and so the 4S phenomena.
This idea may be correct, but it is necessary to provide support from both direct
measurements and calculations. Chang Sun and colleagues mainly use the bond-orderlength-strength (BOLS) correlations, that seem to be heuristic in character, but they show
also that: (1) the results of some DFT calculations on arm-chaired graphene nanoribbons
are, more-or-less, in line with the expectation from BOLS correlations; (2) the results of
scanning tunneling microscopy measurements on Cu surfaces seem to support their idea. I
think that much more details should be provided about the DFT calculations because they
should be able to produce results non-ambiguous with respect to the idea advanced by
Chang Sun and colleagues.
B: The manuscript reports the possible mechanism of 4S (superhydrophobicity, superfluidity,
superlubricity and supersolidity) at the nanometer sized liquid-solid or solid-solid contact.
Authors suggest that the Coulomb repulsion between the “electric monopoles or dipoles
locked in the stiffened solid skin or the solid-like liquid skins” could be responsible for the 4S.
I find that the subject presented in the paper is interdisciplinary and very interesting.
However the conclusion drawn by the authors are too broad to be supported by the data and
evidences presented in the paper.
A number of experiments regarding superlubricity [Reference 10, 11, 13] were
carried out in vacuum using a dry nanoscale contact between AFM tip and sample surface.
In this case, where is electric dipole or monopole located? How do the amount of dipole, or
Coulomb interaction among dipoles, depend on the conductivity of materials (for example,
Mica, graphite, or gold)? How this Coulomb force would be changed in the presence of water
layer between two contact bodies? Furthermore, the Coulomb interaction between these
charges can influence tip-sample adhesion, and then friction force because of the change of
effective applied pressure. However, friction is matter of energy dissipation of mechanical
energy that is dominated by phonon and electronic excitation [For example, Cannara et al.
Science 318, 5851 (2007), Park et al. Science 313, 186 (2006)]. Coulomb interaction or
electrostatic force is regarding adhesion force that is not the fundamental parameter to
describe friction force.
Regarding the superhydrophobicity, authors mention that sp orbit hybridization of F,
O, N, or C generates nonbonding pairs or unpaired electrons that induce dipoles. No
experimental data or evidences are presented in the paper.
Sun CQ/EEE
22
C: This paper represents a significant new contribution and should be published as is.
D: It is an interesting work to study the superhydrophobicity, superfluidity, and superlubricity
at nanometer-sized contacts. The author represents a new mechanism, namely eclectic
repulsive interface, to explain the phenomenon as mentioned above. It is very specialized for
physical and chemistry readers. The mechanism leads to further understanding of 4S
phenomenon.
Behind the quantum and size effect: broken-bond-induced local strain and skin-depth
charge and energy quantum trapping (invited)
in the special volume entitled “Size Effects in Metals, Alloys and Inorganic
Compounds: From Basics to Applications” Book Chapter, pp17-46.
published by Trans Tech Publishers (Switzerland)]
The article is apparently the last of the trilogy on bond order, under-coordination
of atoms, bond strength and energy as well as the relationships of these
atomistic features with size effect, the central theme of the book. Especially
interesting, to me, is the continued evolution of the theories involving bond
order-length-strength (BOLS) to local bond average (LBA) and the implications
of these ideas in studies of nanosolids. Another point mentioned is the classical
continuum theory and its application in case of nanostructures: this is also an
important feature and may grow into an important research topic.
The style of presentation of the propounded science and its interpretation is
very clear and suitable for not only the theorists, but also experimentalists who
are generating new information on size effect, and want their observations to be
validated by basic theory. The article is thus a valuable contribution.
Coordination-resolved C-C bond length and C1s binding energy of carbon allotropes
and the effective atomic coordination of the few-layer graphene, J Phys Chem C113,
16464-7 (2009)
A: The authors discuss the determination of binding energies of carbon allotropes. The
objective of the manuscript is to show that quantitative information about the C1s binding
energy of an isolated atom and its shift can be obtained from the BOLS theory. The results
are interesting and useful.
B: This paper represents a significant new contribution and should be published as is.
The manuscript reports bond length and binding energy variation as a function of atomic
coordination on carbon allotropes. With growing interest in carbon based noble materials
such as carbon nanotube, graphene nanoribbons, and graphite, the work presented in the
manuscript can be very useful and insightful information. I find the results are new and the
conclusion drawn is sound.
Size dependence of the 2p3/2 and 3d5/2 binding energy shift of Ni nanostructures: Skindepth charge and energy trapping, J Phys Chem C113, 10939-46 (2009)
Sun CQ/EEE
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A: Although the chemistry and physics of materials at surfaces and in nanometer scale has
been extensively investigated, the behavior of electrons surrounding the under-coordinated
atoms has not been fully understood. This paper reports a research work with combination of
experimental and theoretical investigations on the size dependence of 2p3/2 and 3d5/2
binding energy shift in Ni nanostructures deposited on TiO2 substrate. Using the Auger
electron and x-ray photoelectron spectroscopes (APECS), the authors determined the 2p
and 3d core level shifts as a function of deposition time. The observed phenomena were
explained with BOLS theory and tight binding band theory. The results show the consistency
between the experimental measurement and theory predictions. The work is interesting and
potentially useful. It will provide some insights into the behavior of surface electrons.
B: While the potential interest in the present version of this manuscript may be limited, I
believe that it should ultimately be published because it may have potential applications in
other areas of nanomaterials. The manuscript has important finding, presently directed at too
narrow an audience, and it is the authors’ responsibility to increase that audience in the
revision. I hope that my suggestions will aid in the revision.
C: The manuscript discusses the size dependence of L and M energy level shifts of Ni
nanostructures deposited on TiO2 using Auger photoelectron spectroscopy (APECS) and
interpret the results using bond order-length-strength (BOLS) which is a tight-binding way of
discuss the effect of reduction of bonds to the energy levels of these structures. The MS
presents experimental results and interpret it with BOLS. The results appear to be in
agreement and the paper is acceptable to publication.
Elucidating the 4f binding energy of an isolated Pt atom and its bulk shift from the
measured surface- and size-induced Pt 4f core level shift, J Phys Chem C113, 14696701 (2009)
A: The work under review is well founded. Nevertheless, authors probably should have
accounted for different surface curvature signs for the external and internal surface of the
cluster, grown on NCT. This can affect the cluster’s shape as the covering layer thickness
increases. Nevertheless, this does not give a reason to doubt in the conducted analysis and
conclusions of the work. The work is worth publishing in your journal.
B: In this paper, Yi Sun and her coworkers describe their study on the surface and size
effects on Pt 4f core level shift based on their originally developed empirical algorithm.
Enhanced catalytic activity of nano-sized Pt clusters on graphite surface is indeed
extensively studied topic. Their analysis is stimulating and thus expected to contribute to the
understanding of the electronic structure of Pt clusters. Description on Pt surface core level
shift was straightforward. On the other hand, the case for nanoclusters is much complicated.
As indicated in Figure 3, the shape factor τ is not a constant value. Additional figures that
illustrate cluster models help understanding of coordination number and shape factor are
suggested.
Size-induced elastic stiffening of ZnO nanostructures: skin-depth energy pinning,
APPL PHYS LETT 94, 131902 (2009)
Sun CQ/EEE
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OVERALL RATING: Excellent
The paper is very interesting and novel. I strongly recommend its publication.
Field emission properties of Si tip arrays coated with N-doped SrTiO3 thin films at
different substrate temperature J Appl Phys 105, 013312 (2009)
This paper describes a systematic and comprehensive investigation of the influence of the
growth temperature of thin SrTiO3 coatings under partial N2 pressure on the structural,
electronic and field emission properties of Si tip arrays. The results are consistently
explained by the increased N doping as function of temperature which causes significant
changes of the crystal structure, XPS core levels, optical band gap and field emission
threshold field and stability. The latter is of high importance for possible vacuum electronic
applications, e.g. flat panel displays. Therefore, this paper is well-suited for publication in
JAP.
Thermo-mechanical behavior of low-dimensional systems: the local bond average
approach, Prog Mater Sc i54, 179-307 (2009)
Editor: This is a good manuscript which we would like to publish in Progress in Material
Science. However, the reviewer has made a number of important suggestions for
improvement. Please pay attention to these points and revise the manuscript accordingly.
Referee: I found this article very interesting, informative and comprehensive. It gives a full
treatment of each topic under discussion and appears to be aimed at a reader with
significant background knowledge. It highlights not only the author’s profound knowledge of
the subject, but also the problems and necessity of deriving experimental evidence to
substantiate the theoretical models under discussion and to ascribe numerical values to
these.
If the author wishes to include the reader with less background knowledge, then a
brief introductory section for each topic might help to lead the readers into some of the more
complex sections. Additional illustrations may also aid the readers when interpreting the text.
As an example, the section on carbon nano-tubes could include a schematic diagram of the
C-C bond in various structures. My understanding is that CNT can be formed from sheets of
one of several orientations and hence have variable values of Y on that basis. A diagram
might help to explain here. The section, however, gave a fascinating insight into the topic,
which I found very informative.
In short, I am happy to recommend the publication of this article after the corrections.
Factors controlling the strongest size of the inverse Hall-Petch relationship, NANO 3,
175-85 (2008)
The new model allows predicting the mechanical properties of nanoparticles. The description
is good and is of significant interest. The scientific merits of the MS are good. The paper is
therefore worth publication, although some changes are recommended before publication to
improve the quality of the presentation.
Pressure-stiffened Raman Phonons in Group III Nitrides, J Phys Chem B112, 50275031 (2008)
Sun CQ/EEE
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A: This work quantitatively studied the pressure-induced Raman phonon stiffening from the
perspective of local bond average (LBA) and deduced an analytical solution to connect the
pressure-induced Raman phonon stiffening to the bonding identities of the specimen and the
response of the bonding identities to the applied pressure. The theoretical results are
consistent with experiments. Therefore, I recommend it for publication in JPC.
B: In this manuscript the authors discussed the pressure-induced Raman phonon stiffening.
They first showed that the well-known polynomial expression for the pressure-induced
Raman shift can be derived by using their recently developed bond-order-length-strength
approach. Existing experimental results of GaN, AlN, and InN were then compared with the
theoretical result that is sound and solid, but not surprising as similar analysis can also be
done by the traditional lattice dynamics theory. Nonetheless, the polynomial coefficients they
obtained will be helpful in establishing deeper understanding of the physical mechanism of
the phonon stiffening.
Nanocavity strengthening: impact of the broken bonds at the negatively curved
surfaces, J Appl Phys 103, 084317 (2008)
Overall, this is an interesting paper that reports a theoretical study of the mechanical
properties of nanoporous materials within the framework of an analytical model based on the
bond-order-length-strength correlation mechanism developed earlier by one on the coauthors. The results of this work may be useful for understanding the mechanical properties
and response to the mechanical deformation of nanocrystalline metals, which is a very
important matter at the moment and for other porous three-dimensional systems as well.
Size dependence of pressure-induced phase transition of nanostructures. J Phys
Chem C 112 (7), 2423-7, 2008
A: The authors examine pressure and size effects on the critical temperature of phase
transitions to quantitatively explain the size dependence of the phase transition pressure of
nanocrystals. The approach used the BLOS mechanism, applied to a core-shell model for
nanoparticles. The authors deduce that pressure compensates for the size-induced change
in Tc that results from lowered cohesive energy of under-coordinated surface atoms. The
fundamental underpinnings of this approach and classical thermodynamics approaches are
clearly related though approach does not directly utilize surface stress or surface energy
concepts. The work is interesting and publication is supported if appropriate clarifications are
made.
B: In this paper the authors develop a theory for the size-dependence of the transition
temperature for phase transformations in nanoclusters. While this is a very interesting and
timely topic, I feel unable to judge the significance and validity of this paper. It is unclear to
me how it is possible to arrive at such an expression without including surface effects
explicitly (these must be included in some way, but I don't see how). Also, is there any fitting
to the experimental data involved? Perhaps I am missing the point of the paper (after all the
analytical expression seems to reproduce the experimental data rather well), but I just can't
make much sense of this manuscript. For these reasons, I do not recommend this paper for
publication in JPC.
Sun CQ/EEE
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Temperature dependence of the elastic and vibronic behavior of Ge, Si and diamond
crystals. J Appl Phys 102, 083524 (2007)
This manuscript provides analytical models to relate the temperature dependence of the
Young's modulus and the Raman shift with atomic bonding properties, i.e. the cohesive
energy, atomic coordination number and bond length.
Concise formulas are developed by the authors to explain the temperature
dependence of the Young's modulus and the Raman shift. A key correlation between the two
properties is also revealed based on the formulas. Although a similar model for the thermalinduced softening of the Young's modulus has been discussed in a previous paper by Gu,
Sun, et al (2007 Physical Review B) for Al2O3 and AIN, the model for Raman shift as well as
the correlation between them are believed to be completely new. The explanations for the
difference between the EB(0) values from Raman shift and elastic modulus are reasonable.
These findings by the authors explain very well the thermal softening of the elastic
and vibronic properties of a group of materials at a fundamental level. The general approach
to relate the macroscopic properties to models at atomic levels is quite inspiring. The
mathematical derivations are straight-forward, the logic is clear and the language is fluent.
Size, temperature, and bond nature dependence of Young’s modulus and its
derivatives on extensibility, Debye temperature, and specific heat of nanostructures.
Phys Rev B 75, 125403 (2007).
A: I find both the topic and the proposed approach in the manuscript very interesting. It is
generally well written.
B: The paper concerns the interesting item: particle size elastic modular dependence. The
authors underline that these dependences may have different character at different
temperatures. It sounds reasonable. However, I'd like to make one remark. Born's criterion
of melting actually might be wrong. I mean that all substances have finite (non-zero) values
of elastic constants at Tm. So vanishing of Young modulus corresponds to instability
temperature Tinst~1.2-1.5Tm. It is well known and there is a great background of this item.
So all equations should be rewritten (or at least authors should discuss that the
dependencies are qualitative ones since they simply reflect the trends at heating).
Atomistic origin and temperature dependence of Raman optical redshift in
nanostructures: a broken bond rule (invited), J Raman Spect 38(6), 780-8 (2007)
A: The paper presents a theoretical analysis of the mechanisms of the size and temperature
induced red-shifts in the Raman spectra from nanostructures. The topic is important since
the mechanisms of the red sift is still the subject of debates and can vary from the sample to
sample. The proposed model can help in the interpretation of the experimental data.
B: The authors present a theoretical discussion of the redshift of optical phonons in
nanoparticles as size and temperature are varied. This work should be published.
C: It is a nice piece of work describing a sophisticated consideration of the acoustic modes
in the freestanding NPs or the embedded NPs from the perspective of polarization by adding
Sun CQ/EEE
27
the effect of matrix to the previous models of NP-Surf coupling. A detailed sample of
comparison between the calculated and the measured result would be necessary and more
convincing, as the readers are keen to known the nature of the acoustic modes and the
consistence between modeling and measurement.
If the work refers the LFR acoustic modes that shift to the blue side with the
decreases of NP size and disappear when the NPs approach infinitely large, this approach
may not be appropriate, instead, inter particle interaction may dominates [Sun et al, PRB 72,
134301 (2005)]. Therefore, presents of their results may justify the validity of the current
approach.
The kinetics and modes of gold nanowire breaking J Comp Theo Nanosci 5, 1450-3
(2008)
A: The authors performed molecular dynamics calculations for studying the lifetimes and
breaking modes of an Au nanowire under various mechanical and thermal stimuli. They
found that the duration of wire broken could be affected by the thermal energy and tensile
strength and a higher temperature and stronger tensile force could break the wire swiftly.
However, as the tensile force varies, the wire rupture occurs in three different regions: f > 0.1
nN/atom, 0.1 nN >= f > 0.018nN/atom and f <= 0.018 nN/atom, corresponding to the abrupt
breaking, structure transformation induced breaking, and non-breaking, respectively. The
work is well done and the results are interesting. Recommend acceptance after a minor
revision.
B: The lifetimes and breaking modes of an Au nanowire under various mechanical and
thermal stimuli were studied using molecular dynamic calculation, which is a very interesting
topic in the field of nanoscience and nanotechnology.
Atomistic origin, temperature dependence, and responsibilities of surface energetics:
An extended broken-bond rule, PHYS REV 75, 085427 (2007)
A: The authors clarified several important points that remained open in the first version.
Although questions still remain in the present form of the article, it is highlighted correctly
and the authors took real further steps to clarify the still existing confusion about the surface
energy. It would surely be useful to publish these results for a wide audience of scientists
motivating them to give the next steps in this field. Therefore I suggest publish this work in
the present form without further revision.
B: The approach proposed might be useful to understand complex surface phenomena and
seems to work in the cases studied. I believe the present form is suitable for publication in
Phys. Rev. B.
Electronic process of nitridation: mechanism and applications, PROG SOLID STATE
CHEM 34(1), 1-20 (2006)
The review work reports on an extension to nitrides of the "bond band barrier" (BBB) concept
initially used for oxides (authors work in Appl. Phys Lett. 1998). In as far as the scheme fits
with, and explains behavior of, different classes of nitride systems, the work deserves to be
Sun CQ/EEE
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published. From the basic scientific point of view there is an obvious lack of computational
illustrations (from published literature) to the discussions. For example, for the comparison
between the DOS of nitrides versus oxides (cf. figs.2). Then, there is a point that the authors
might wish to address: How would the BBB model fit within graphitic like C3N4 which is
known to possess holes within the graphitic layers, surrounded by nitrogen lone pairs.
The referee suggests the authors to be more open as to other possibilities of
explaining the phenomena observed in nitrides such as from density functional calculations
while several works on nitrides in this theoretical framework have certainly provided
significant progress in the explanation of their physical properties within different classes.
Size-induced undercooling and overheating in phase transitions in bare and
embedded clusters, Phys Rev B 73, 075408, 2006.
A: Sun and coworkers provide a background of experimental studies of size-induced effects
on temperature of phase transitions, and describe application of bond-order-length strength
(BOLS) theory. They show that a variety of phase transitions (magnetic, solid-liquid and
liquid-vapor) can be satisfactory modeled with BOLS approach over a wide range of particle
sizes. Studies of basic phase transitions in nanoscale materials are of great fundamental
importance to modern condensed matter physics, and at least from the "subject" point of
view such material is well within the scope of Physical Review B. One of the most intriguing
questions that the manuscript attempts to answer is the recently discovered anomalous
behavior of melting point for nano-sized clusters of Ga and Sn, which is significantly higher
than bulk melting point - opposite to lowering of melting point typically found in most
materials as the size of particles decreases.
B: Sun and coworkers provide a semi-phenomenological theory based on bond shortening
near the surface or interface to explain size-dependent behavior of melting points and
temperatures of other phase transitions. The manuscript clarifies assumptions made in
theoretical approach and underscores the semi-phenomenological nature of BOLS theory.
From a purely scientific point of view the paper is in good shape.
Size-induced acoustic hardening and optic softening of phonons in CdS, InP, CeO2,
SnO2, and Si nanostructures, Phys. Rev. B 72, 134301(2006)
A: The manuscript reports a theoretical study of size-induced acoustic hardening and optical
softening of phonon modes in CdS, InP, CeO2, SnO2 and Si nanocrystals. Based on a bond
order-length-strength analysis, the authors showed that the optical softening stems from
atomic cohesive energy weakening of surface atoms, while the acoustic mode hardening
arises from intergrain interaction. The results obtained are original and interesting. This
manuscript merits publication in PRB.
B: This paper is in an interesting topic. It deals with the shifts of Raman acoustic and optic
modes in nanosolids. These generally shift towards higher and lower vibration frequencies in
the nanosolids, respectively. Size effects and confinement are in the core physics of these
materials.
Effect of Surface bond-order loss on the electrical thermal conductivity of
polycrystalline thin films, J Appl Phys. 98, 113707 (2005).
Sun CQ/EEE
29
The paper contains materials of good quality to justify publication after minor revision.
Effect of Surface bond-order loss on the electrical resistivity of metallic
polycrystalline thin films, Phys. Rev. B 72, 155417 (2005)
In the manuscript, the classical resistivity of thin metallic polycrystalline films is calculated.
The authors enhance the well-known model of Mayadas and Shatzkes by taking into
account the additional square well scattering potentials at the grain boundaries. Using the
Fuchs-approach, the effect of the surface scattering on the resistivity is considered as well.
Fit to the experimental data of Kaestle et al. and Fenn at al. is presented. In agreement with
the experiment, decrease of the surface Debye temperature for thinner films is found. The
paper contains enough significant new physics to warrant publication in the PHYS REV B.
Theory of size, confinement and oxidation effect (Chapter I) in the “Oxide
nanomaterials” Eds. Marcos Fernández-García and José A. Rodriguez, John Willey &
Sons, 2005.

Together with Marcos Fernandez-Garcia, I am editing a book for John Wiley & Sons on
the synthesis and applications of oxide nanoparticles and nanostructures. The
attachment shows the contents of the book and authors that have already agreed to
contribute. One of the chapters (I) deals with the theory of size and confinement effects
in oxide nanoparticles. I am impressed with your article in J. Physics. D 34 (2001) 3470
and wonder if you will be interested in writing this chapter describing your recent work
and giving an overview of the topic.

We congratulate you for writing a very nice chapter on the theory of size, confinement
and oxidation effects. We would like to express our gratitude for sharing your chapter
with time to send you back some ideas that maybe useful for providing the theoretical
background for subsequent chapters. Mainly, such ideas are related with experimental
results concerning size-influence on oxide properties which may not be fully covered in
the text. On the other hand, we believe that the way you explain the influence of size on
main experimental observables is quite clear and is rather useful for chapters following
yours.
Thanks for a nice contribution to the book. Marcos Fernández-García and José A.
Rodriguez

Book Review “Putting an ‘O’ into nanomaterials”, Nanotoday 2(5) 46 (2007) - P. David
Cozzoli, National Nanotechnology Laboratory of CNR-INFM, Lecce, Italy
Chapter 1 by CQ Sun uses quantum-mechanical concepts to illustrate how lattice
distortion, electronic state density changes, and oxidation-induced charge redistribution
evolve with size at the nanoscale and jointly impact on optoelectronic responses and
chemical reactivity.
Melting point oscillation of a solid over the whole range of sizes Nanotech 16, 1290-3
(2005)
Sun CQ/EEE
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The paper deals with a problem that has attracted significant interest recently. It is an
attempt for consistent understanding and quantified information of the size dependence on
the melting point Tm of a nanosolid, containing atoms of Ga or IV-A elements. The authors
extend their bond order-length-strength (BOLS) correlation mechanism to the problem which
indicates the bond-strength gain as an atomic CN imperfection. The paper belongs to the
current activity on the subject of this group. I have examined the manuscript and I found it
acceptable for publication.
Impact of bond order loss on surface and nanosolid magnetism, ACTA MATER 53,
3207-14 (2005)
A: This is a fine technical and well-organized paper, using simulations to study magnetism of
nano-structured materials. The only problem I have is that the contents are more physics
than materials. I would like to leave the question to the editor if this paper is suitable for
publication in AM.
B: Magnetization in nanoparticles is a research area of significant current interest, both from
the points of view of fundamental and applied science. The paper appears sound and
reasonable, with a sufficient amount of new information to warrant publication as it is.
Impact of bond-order loss on surface and nanosolid mechanics. J. Phys. Chem. B109
415-23 2005
The paper considers an analytical solution for the size and temperature dependence of the
mechanical strength and compressibility of a nanosolid based on their original BOLS model
and some mathematical treatments. The authors prove theoretically that the grain size
dependence of mechanical strength or the Hall-Petch relationship is not obeyed as grain
size decreases to about 10-20 nm, which are related with the bond decrease on the surface
and melting temperature. The work gives new insight on this traditional theory which is
activated in recent years due to progress of nanotechnology. Thus, the paper is worthy to
publish.
Dielectric suppression of nanosolid silicon, Nanotech 15, 1802-6 (2004)
A: The paper contains interesting insights about the origin of dielectric suppression in
nanosolids. The authors base their models on the bond-order- length-strength correlation
(BOLS) that they have been using successfully in the last years to gain insight on the size
dependence of almost all detectable and imaginable physical properties of nanosolids. The
application to the problem of dielectric suppression is interesting and physically sound. This
paper is a successful combination of theoretical modeling and experiment on the interesting
topic of dielectric properties of nanosolids. The overall presentation is very good. The paper
can be published as it is.
B: This is a very interesting submission which indicates how more realistic theoretical
calculations of the properties (particularly electrical properties) of a spherical silicon
nanoparticle may be derived. Building on the authors’ earlier work, explicit account is taken
of the difference between the environment of the surface silicon atoms and that of the inner
Sun CQ/EEE
31
atoms. The authors might emphasize more the way in which the ratio of surface to inner
atoms depends on the size and shape of the particle.
Surface silicon atoms will be linked to either three or two inner atoms. The authors
discuss the effects of this in terms essentially of electronic field migration – a chemist would
describe it as enhanced multiple bond formation between the Surface and inner atoms! A
more detailed estimation of these effects as they diminish on moving further away from the
surface will perhaps be addressed in future work. Despite the assumptions made, the
authors show that there is pleasing agreement between the experimental results and the
calculations described here. I recommend that this work be published in “Nanotechnology”
as is.
Surface and Nanosolid Core-level Shift: Impact of Atomic Coordination-Number
Imperfection. Phys Rev 2004; B 69: 045105.
The manuscript gives good overview with an extension of the Author's approach to the core
level binding energy shift. The considerations are well supported with references to the
Author's previous work. The present approach to XPS energies is certainly worth publishing,
as it could provide a useful tool for interpretation of the experiments, or a way to determine
core level position and shift contributing to our understanding.
Breaking limit of atomic distance in an impurity-free monatomic chain. Phys Rev B 69,
245402, 2004
This paper offers a theory for explaining the divergence of breaking bond length in a single
atomic chain system as a function of temperature, as the melt temperature of the chain is
approached. The theory is an alternative to the explanation that impurity atoms are
responsible. The theory depends greatly on the behavior of the compressibility as this melt
temperature is approached, which is interesting, novel, and even more reasonable.
Coordination imperfection suppressed phase stability of ferromagnetic, ferroelectric,
and superconductive nanosolids. J. Physics. Chem. B 108 1080-4 2004
The paper models the size dependent Curie transition temperature of several Physical
phenomena with a unified model. The model predictions are in agreement with the
experimental results of ferromagnetic, ferroelectric and superconductive transition
temperatures. Although the work is concerned with the application of the original model of
the authors, the idea of the critical volume in Eq. (11) is novel and interesting. Thus, the work
presented is sound and should be published in JPCB.
Elucidating Si-Si Dimmer Vibration from the Size-dependent Raman Shift of Nanosolid
Si. J PHYS CHEM B 108, L3404-6, 2004
The paper considers the Raman shift of nanosized Si based on Einstein equation and their
original BOLS model with some mathematical treatments and derived information of dimer
vibration from the size dependent data, which is novel and useful. The authors also prove
theoretically that the magnitude of surface atomic vibration is always higher than the bulk
value and keeps constant at particle size greater than one nanometer, which was assumed
Sun CQ/EEE
32
long time ago yet failed to be proved. Thus, the paper is worthy to publish.
Length, Strength, Extensibility and Thermal Stability of a Metallic Bond in the Gold
Monatomic Chain. J. Phys Chem. B108, 2162-7, 2004
The fabrication and characterization of metallic monatomic chains (MC) and the
corresponding theoretical interpretation are one of the most important challenges in recent
years. Since the theoretical background of this new material family is unclear, the authors of
this work attempted to find a physical explanation based on calculating some physical
quantities of Au MC, such as bond length, bond strength, melting temperature and plasticity
using their original bond-order-length-strength (BOLS) theory. Owing to the scientific and
technological importance of MC, the obtained new insight enriches our understanding of the
MC. This work is also meaningful as commented in the manuscript on the present theoretical
results that are conflicting, while the authors give a different way of approach and have
provided a consistent explanation based on calculation clarifying the mentioned concerns.
Dimension, strength and thermal stability of a single C-C bond in carbon nanotubes. J
PHYS CHEM B 107, 7544-6 (2003)
A: According to the facts that the product of the Young’s modulus and layer atomic distance
of nanotubes is approximately a constant and the melting temperature of the single wall
carbon nanotube is lower than that of the multi-wall carbon nanotubes, the authors consider
the physical and chemical nature of the facts based on authors’ theory. In light of the theory
with solving a group of simple equations, the authors find the above phenomena, which
seemed to be conflicting, can be clearly interpreted by their original bond-order-lengthstrength (BOLS) theory. When the above two data are incorporated into their theory,
quantitative results for the bond length contraction and the bond strength enhancement of
nanotubes are obtained. Owing to the scientific and technological importance of the
nanotubes, the above new insight may enrich our understanding of the physical and
chemical natures of nanotube structures.
B: The paper addresses an interesting issue that has to do with the meaning of Young’s
modulus in a flexing single-walled nanotube. Since the wall is a single atom wide, then the
question arises ‘what is the equivalent wall thickness if we treat the nanotube as an elastic
continuum?’ The authors conclude that the answer is 0.142 nm. They go on to assert that
the C-C bond length is 0.116 nm long, representing a contraction of ~18.5% relative to
graphite. The authors present a bond order-length-strength argument based on statement
about the coordination number of carbon atoms. The equations are solved using known
values for the melting temperatures for bulk graphite and curved graphite, along with
measured values for Yt to obtain the bond dimensions t. The analysis is reasonable and
provides certainly an important result, including a nice way to interpret the energetics of
carbon nanotubes.
Distinguishing the effect of surface passivation from the effect of size on the photonic
and electronic behavior of porous silicon, J APPL PHYS 96 1704-8 (2004)
The subject matter is of great current interest and therefore justifies publication as it explains
Sun CQ/EEE
33
quantitatively the band-gap expansion, core-level shift and dielectric suppression of Si
nanosolids passivated by plasma fluorination. The work provides a possible way to tune the
optical and dielectric behavior of the nanostructured silicon, and therefore, allows a potential
application of porous Si as optoelectronic materials. Moreover, the experiment is interpreted
by authors early model with good consistence.
Size dependence of the 2p-level shift of nanosolid Silicon, J. PHYS CHEM 2003; B107:
L5113-5
A: This manuscript presents research of such originality and current interest to justify its
publication AS IS. It explains quantitatively the core-level shift observed for Si nanosolids.
The fact that the lack of coordination of the surface atoms leads to changes in the bond
energies and therefore to changes in the core-level energy is convincing.
B: This paper has established a size-dependent model to describe the 2p-level shift of
silicon nanocrystals based on the BOLS correlation mechanism proposed by the author
(SCQ). The model has been found to be in agreement with the XPS experimental results.
The model suggests a new way to obtain quantitative information about the atomic trapping
energy of the 2p electrons of an isolated Si atom and the binding intensity of bulk crystal,
which goes beyond the capacity of currently available techniques. Therefore, the manuscript
should be published after minor typo-error corrections.
Photoluminescence of Si nanosolids near the lower end of the size limit, J PHYS
CHEM B 106: 11725-11727, 2002
A: This article presents an interesting study on the photoluminescence of Si nanoparticles.
The topic is of great current interest and the work is good and sound and should be
published in JPCB.
B: The paper presents interesting results on the size dependence of the PL line in Si
nanostructures. The authors suggested and successfully used "bond order-length-strength”
model to describe these results. I recommend publishing this paper in the JPC as it is.
Size effect on the electronic structure and the thermal stability of a gold nanosolid.
ACTA MATER, 52, 501-5, 2004
Effects of surface passivation and interfacial reaction on the size-dependent 2p-level
shift of supported copper nanosolids. ACTA MATER 51, 4631-6 (2003)
Dear Professor Sun: I have received a favorable review on your paper and have accepted it
for publication. Thank you for publishing your article in ACTA MATER. Best wishes. Subhash
Mahajan
Upper limit of blue shift in the photoluminescence of CdSe and CdS nanosolids,
ACTA MATER 50, 4687-93 (2002)
This paper presents a theoretical argument for the nanocrystal size dependence of the PL
wavelength of CdSe and CdS nanocrystals. The main argument relates the effective gap of
Sun CQ/EEE
34
the crystal to that of the bulk corrected by surface energy that appears to be related to bond
relaxation on the surface. The validation for this approach is to compare the available
experimental data on PL shift versus size with their paramerized model, which show better
than the simple quantum confinement model proposed by other authors which gives a D-x
dependence. The idea presented by the authors is of merit and the paper is recommended
publish after some minor revisions.
Bond-order - bond-length - bond-strength (BOLS) correlation mechanism for the
shape-and-size dependency of a nanosolid. J PHYS CONDENS MAT 14, 7781-95 (2002)
A: The shape and size dependency of the physical and mechanical properties of a
nanomaterial is one of the important key issues in nanoscience. The manuscript presents a
theory relating the unusual change of different properties of nanocrystals to the bond
strength of surface atoms that experience coordination (CN) reduction. The theory considers
that the CN-reduction induced bond strength enhancement contributes to both the total
cohesive energy of the solid and to the energy density in the relaxed surface region, either of
which determines the physical property change. Modeling predictions on some physical
properties of nanomaterials agree with experimental and theoretical results. The model gives
a new way of thinking about the size and shape dependency of nanomaterials. Therefore,
the manuscript should be published.
B: The authors are presenting a simple phenomenological study of the shape and size
dependence for nanonsolids in terms of chemical arguments as bond-order, bond-length and
bond strength. They show that for a large class of materials, covalent, metallic, ionic,
decreasing the coordination number, as for instance for a surface atom, the bond becomes
shorter and stronger. They are able to reproduce many Physical properties in terms of the
ratio of surface atoms to bulk atoms and a relationship of the modification of the bonding
energy in terms of bond contraction. This paper provides a guideline to construct
nanomaterials with specified shape and size dependence. The paper gives a consistent
understanding of the size dependence of a considerable number of properties of nanonsolid.
In conclusion I recommend the paper be published as it is.
An extended 'quantum confinement' theory: SURF-coordination imperfection modifies
the entire band structure of a nanosolid, J PHYS D 34: 3470-3479, 2001
A: The results presented in the manuscript are interesting and seem to contribute to an
explanation of the experimental observations. I thus recommend publication.
B: This is an interesting, however potentially quite controversial paper. If the authors are
correct, this paper will indeed rank as one of the most important papers on nanomaterials.
Prior to publication, this referee has several serious scientific concerns that need to be
addressed, and additional evidence supporting the proposed model is necessary.
Proof that band-gap expansion is actually due to bond contraction at surface s and the
rise in surface -to-volume ratio, and not to the commonly accepted quantum confinement
(QC) argument would indeed be significant finding, and highly worthy of publication.
Because of the potential for controversy, it is most critical that this manuscript contain a full
discussion comparing and contrasting the proposed mechanism with the commonly
accepted QC mechanism. Such a discussion is not present within the paper. The most
Sun CQ/EEE
35
widely studied nanoparticles are those composed of II-VI semiconductors. It would be
valuable if the authors were to comment on how their theory compares with the experimental
data from such systems.
Board Adjudication: The paper is concerned with an important question about the Physical
origins of evolution of the band structure with reducing size of solid particles. The authors
claim to show that the main role in the band gap expansion belongs to the contraction of
surface bonds and to the rise in the surface to volume ratio in small particles. This is in
contradiction with the quantum confinement model, which is now widely accepted. Therefore
the readers will expect from the authors clear arguments showing what is wrong with the
quantum confinement model that is based on very general concepts (standing electron
waves in a potential box). The original results of the authors are presented without
necessary details, which would demonstrate the reliability of their statements. In this respect,
the paper is not self-contained. Therefore, I recommend a substantial rewriting of the text
with the aim of a more lucid presentation of authors' ideas. In my view, the remarks of the
second referee are justified and should be taken into account.
Report on revised version: The authors have done a nice job of revising what initially was
a scientifically weak document. This referee would recommend publishing as is.
Dielectric suppression and its effect on photoabsorption of nanometric
semiconductors. J PHYS D 2001; 34: 2359-62.
A: The authors discuss dielectric suppression and photoabsorption in nanometric
semiconductors, in particular the dependence of the dielectric susceptibility on the particle
size. The paper is sound. An important point of the work is the striking simplicity of the
model. I think that the value of this model will become clearer if discussed in the community.
Therefore, I suggest publication of the manuscript.
B: The idea of the work is interesting, so the paper deserves publication. However, it would
be worthwhile to discuss other approximations in the text, which would strengthen the
statement made in this paper.
Bond contraction and lone pair interaction at nitride surfaces, J APPL PHYS 2001; 90:
2615.
A: This original paper mainly focuses on the detailed study of the mechanical properties of
nitride surfaces, poorly known at this time, and notably obviously gives for the first time by
extrapolating hardness surface characterizations a very clear and interesting evidence of the
bond contraction at the TiCrN surface. I consider that this paper is worth to be published as it
is in JAP.
B: This is an interesting and timely paper which reminds us – and indeed extends the theory
of – how surface properties differ from those of bulk and how important this effect will be
when considering the behavior of materials used in micro-mechanical systems and nanoscale devices etc. The paper is concise, well-written and fairly referenced.
Sun CQ/EEE
36
The lattice contraction of nanometre-sized… J PHYS-CONDENS MAT 1999; 11: 4801-3.
The titled article reports a simple and plausible analysis on how lattice parameter depends
on particle size in nanoclusters. The analysis is quite straightforward and credible. The topic
is timely and important. Nano-size structures, which have been shown to have enhanced or
unusual physical properties are important technologically. Therefore, it is imperative in
understanding the structural properties of nanoparticles which no doubt influences Physical
properties. The author explains lattice contraction in light of a "surface bond contraction"
model. To do so, they make use of Pauling's finding that the metallic radius contracts with
reduction of the coordination number. All in all, the paper deserves rapid publication as a
letter in JPCM.
Oxidation electronics: bond-band-barrier correlation and its applications, PROG
MATER SCIE 48: 521-685 2003.
You have presented an impressive set of nice works that deserve rapid publication. Please
pass me all the figures as soon as possible for processing. – M. Ashby, (The editor)
Crystalline carbonitride forms harder than the hexagonal Si-carbonitride crystallite. J
PHYS D 34: 1430-35, 2001
A: The manuscript is well presented and suitable for publication. It contains original
contribution and pretty well presented with satisfactory English. Therefore, I recommend
publication except for the minus revision.
B: A beautiful paper, which was very easy to review. Despite this, the paper could be even
more interesting in adding some thermadynamical consideration, about competition between
C-H bond energy which is 4.3 eV and C-N bond energy which is 3.16 eV, and explaining
how difficult it is to produce a structure with C-N bonds when hydrogen is present and
bonded to carbon at the surface. Also again never to forget the theory of density of enthalpy,
which has been also confirmed by other physical theoretical consideration by J. Robertson in
1991, saying that hardness is a sum of bond energies per unit volume. Even if the
covalent distance of the C-N bond is shorter than for diamond, the fact that the C-N bond
energy is only 3.16 eV(instead of 7.2 eV for diamond) can explain the lower hardness of
C3N4 than for diamond, despite the remarkable approach of Liu and Cohen, with the very
well done comments in this paper. The shown role of silicon is also remarkable, as it may
explain how to overcome the thermodynamical competition. It appears quite clear that
hydrogen has to be removed before a nitrogen atom can be placed in substitution.
Preferential oxidation of diamond {111}, J PHYS D 2000; 33: 2196.
A model of bonding and band forming that was developed for metals and extended to oxides
and nitrides by one of the author (SCQ) has been applied in this paper, to explain the
preferential oxidation of diamond in the {111} planes compared to the {220}. The authors
also discuss the graphitization in vacuum of diamond that occurs with no crystal orientation
selectivity at a higher critical temperature in comparison with the oxidation process. The
model provides an interesting and credible explanation for the preferential oxidation of
Sun CQ/EEE
37
diamond.
Improving diamond-metal adhesion with graded TiCN interlayers, J APPL PHYS 2002;
91: 2051.
This paper is original and reports very interesting results about the way to decrease the
intrinsic stress that remain in the deposition of diamond film on metal substrates by means of
PECVD. Based on their previous data of O, N, and C –metal bonds, the authors predict the
interfacial stress behavior and they correlate their experimental results to these data and
finally make the designed buffer layer that has been proven successful. Moreover, the paper
is easy to read and attractive.
Thermally tuning of the photonic band gap of SiO2 colloid-crystal infilled with
ferroelectric BaTiO3, APPL PHYS LETT 2001; 78: 661.
“Newsbreak” at Laser Focus World (April, 2001, p101):
Ferroelectrics constitutes a special group of materials with high dielectric constants and
tunable dielectric properties that vary with external conditions, such as temperature, electric
field, and pressure. Introducing such materials into a photonic crystal could thus help
modulate its bandgap. In line with this, researchers at Nanyang Technological University
(Singapore), working with colleagues at Tsinghua University (Beijing, China), have
synthesized a silicon-dioxide colloid crystal infilled with barium titanite (BaTiO3). The process
combined a self-assembly method with a sol-gel technique. In the vicinity of the ferroelectric
phase-transition point of BaTiO3 (100 to 150 C), the photonic band gap of the resulting
assembly exhibited strong temperature dependence. At the Curie point, they identified a 20nm red-shift in the band gap. This is also where optical transmittance is at a minimum.
According to the scientist, the tuning of the band gap could be used not only for simple on-off
switching, but also in devices requiring more localized control of light propagation.
<1> A model of bond-and-band for the behavior of nitrides, MOD PHYS LETT 1997;B11:
1021.
<2> Spectral correspondence to the evolution of chemical bond and valence band in
oxidation, Ibid 1997;B11:1103.
I should like to review these papers together as they are closely related and of equivalent
interest. In the first paper, the author turns to a band-and-bond model and established it to
account for the physical properties of nitrides. The author explains the origins of N-enhanced
magnetization, the blue-shift and oxide light emitting as well as N-lowered threshold of cold
cathode in diamond. In the second paper, the author uses the same band-to-bond model to
explain the outstanding features in the distribution of states near the Fermi-level of a metal
due to chemisorbed oxygen. This leads to an understanding of the O-metal interaction. What
is most interesting in both the papers is the Physical and quantum-chemical insight, which
the author conveys in his work. The subject matter is of topical interest in explaining
outstanding experimental data. The papers are extremely well written, readable, well
referenced and interesting. I recommend that both be published as they stand.
Sun CQ/EEE
38
Angular-resolved VLEED from O-Cu(001): Valence bands, chemical bonds, potential
barrier, and energy states, INT J MOD PHYS B 11: 3073-3091 1997
The paper addresses the interesting problem of decoding VLEED spectra to obtain
information on surface geometry, potential and electronic structure. Decoding of the fine
structure is a very important problem and the models proposed so far have been rather
crude. Sun proposed a decoding technique that rewards us with understanding of surface
bond formation, dislocation of surface atoms and, in particular, the non-uniformity and
anisotropy of the surface potential barriers. Sun's analysis of experimental results from OCu(001) surfaces clearly indicates the power of his method of analysis and amply justifies
the assumptions he makes while setting up the model. This work, second in a series
submitted here, is both significant and of considerable interest to surface science.
Referencing is comprehensive and the text clear and concise. I strongly recommend
acceptance of this paper.
On the nature of the O-Rh(110) multiphase ordering, SURF SCI 1998;398: L320-L326.
A: This is a very nice piece of work on the origin of multiphase ordering in the O/Rh(l10)
system. In contrast to earlier work on this system, the apparent "missing row" structures
observed with STM are interpreted as a purely electronic effect which results from hybridized
O-2-structures on the surface. Although I am not entirely convinced by this explanation, the
work is highly interesting and original and deserves rapid publication as a Letter, since it
surely will immediately stimulate further work on this controversially discussed subject.
B: I am uncertain of the validity or otherwise of the theoretical methods used in this paper,
but I feel it makes a new and interesting contribution to the structure of oxygen/Rh systems.
The findings are also controversial, and so will stimulate debate, which is, after all, the
lifehood of science.
A model of bonding between oxygen and metal surfaces, J PHYS CHEM SOLIDS 58:
903-912 1997
A: The model proposed is simple and interesting in understanding the oxygen adsorption
induced reconstruction on metal surfaces. Since not all the structures of oxygen-metal
systems are analyzed, it is not easy to judge whether this model holds in general or not.
However, as far as oxygen-copper systems are concerned, this model looks working. The
proposal of this model should give some impact in understanding oxygen-metal surfaces.
Thus, I agree the publication of this paper.
B: The manuscript contains a very nice overview of experimental and theoretical
observations concerning oxygen adsorption and reconstruction, on transition metal and
noble metal surfaces. It proposes a model that ties together the various observations. While
the model is phenomenological in nature and thus does not reveal the underlying basis for
the observed behavior it provides a challenge to total energy and electronic structure
calculations and a good way to think about these systems. This clearly merits publication.
Sun CQ/EEE
39
Modeling of non-uniform electrical potential barriers for metal surfaces with
chemisorbed oxygen, J PHYS-CONDENS MAT 1997;9: 5823-5836.
A: This work describes an approach to theoretically describe electronic surface features
which are relevant for both STM/STS and VLEED experimental results. In particular, it
concentrates on the localization of electrons induced by a strong electron acceptor, namely
oxygen atoms. The main new idea is the development of a single variable parameterized
model for the nonuniform surface potential barrier, locally induced by oxygen chemisorption.
The results of the calculation are compared with experimental VLEED and STM data and
describe them quite reasonably. The results described here are novel, very interesting and
reasonable. They are of high interest to the readers of J. Phys. Cond. Matt. Therefore, I
recommend publication in J. Physics. Cond. Matt. in its present form.
B: The author has attempted to deal theoretically with some difficult and interesting data in
an original and imaginative manner. The mission appears to be ambitious and the approach
evidences ingenious features. The individual components such as the figures, formulae and
mathematical assumptions seem reasonable enough in each localized consideration. In this
reader's judgment, it is the writer's responsibility to make a convincing case for achieving
overall creditability. In the statement (Ils.3-4 from the bottom of p.5), the unanswered
question remains "has a convincing schematic and analytical SPB model been developed?"
It appears that the overall paper in its present form fails to make a convincing case in
total when all the calculations, interpretations and arguments are put together. Hence,
publication in its current form is not recommended. Since this may be an individual response,
referral to reviewers who are theoretical specialists in calculation using highly localized
variable potentials may present an alternative option.
Board member adjudication: This is an interesting attempt to go beyond a onedimensional model to describe the electron dynamics near the surface. A reasonable model
is developed and the ramifications presented clearly. I am of the opinion that this work
should be published as stands, but would advise the authors to critically read the ms again
to detect grammatical and spelling inconsistencies.
2. peers’ correspondences
From: Fuchs, Elmar Christof [mailto:ElmarChristof.Fuchs@wetsus.nl]
Sent: Tuesday, 30 June, 2015 9:52 PM
To: Sun Changqing (Dr)
Subject: RE: Greetings
Dear Chan Qing,
thank you for your mail, I downloaded the two water related papers. I actually do not know where I will see y
meant that literally), but it would certainly be a pleasure to do so. If you the “Soul of Water” is finished, pleas
look forward to reading it.
Kind regards and friendly greetings,
Elmar
Dear Prof. Sun,
Thank you so much for sending me your nice paper on Chem. Rev. I have briefly browsed it and has
Sun CQ/EEE
40
already intrigued very much. It looks provided very thoughtful insights for surface bonds. We will study it
carefully.
It was great to meet you in the conference. If you come to China, please drop me an email. I will be
very happy to invite you give a lecture here so we can learn your research.
Thanks again and best regards,
Jun
********************************
Prof. Jun Li, PhD, AAAS Fellow
ChangJiang Chair Professor
Department of Chemistry
Tsinghua University
Beijing 100084
China
E-Mail: junli@tsinghua.edu.cn
Tel: +86-10-62797472 (Office)
Brenda Bent | Monday, Nov. 11th | View on IFL Science
NO, Some Asians did NOT "just" figure this out, this was discovered by AMERICANS & I
learned this little fact about hot water freezing faster then cold water because of the ...
T. Robert Ljung replied | Monday, Nov. 18th | View on IFL Science
Actually up until now everything has just been guesswork about what is happening during
the Mpemba effect. These guys actually did prove and therefore discovered it.
As simple as that.
552 additional comments | View the full discussion on IFL Science
Dear Prof. Sun,
I have read your papers regarding the BOLS correlation theory. It is so great you developed
a good theory to describe the dependence of core level energy on coordination numbers.
Recently I am studying the binding energy of graphene with different number of layers and
the BOLS theory can apply to my study, similar to your work in JPCC 2009, 113, 1646416467. I have a basic question about the core level C1s binding energy and need your help.
What is the definition of the C1s binding energy, E1s(z), in BOLS theory? Is it from C1s core
level to vacuum level? Or other definition (e.g., core level to Fermi level)? This definition is
important to the interpretation of my experimental results.
I will appreciate very much that you can spend your time in answering my question. Thank
you.
Best regards,
Forest Chien, Department of Physics, Tunghai University
Forest Chien <fsschien@thu.edu.tw>
Dear Chang Qing SUN,
Thank you very much for copies of your works. I will think how I could use them in my
studies. In fact we use a very different approach and language in our investigation. As I
understood your approach is based on quantum (might be even classical) calculations of
separate molecule (numerical calculations). Contrary to that I am interested on many particle
effects, and I am trying to elaborated qualitative models, which refects a qualitative behavior
of ice. I think that is a characteristic difference between chemical and condensed matter
Sun CQ/EEE
41
approach.
For example, one of your articles is about symmetrization of hydrogen bond. I also ask
myself why hydrogen bond is asymmetrical and how one could symmetrize it (for example
by pressure). I've enclosed a reprint of my work on the problem (and a reprint of Frank
Stillinger similar work) to illustrate the difference between approaches. Nevertheless both
approaches could be useful and complementary each other. Thus I will use your in my future
studies.
Sincerely yours
Ivan A. Ryzhkin
I looked over some of your papers with interest. Your approach to nanoscale structure properties relationship is very realistic and so very useful. We have been doing structure
studies on nanomaterials for quite a time: have studied several systems. Attached are a few
more papers of my group.
I guess we could do a good job collaborating: We may provide finite/real size and shape 3D
structure models (tested and refined against experimental XRD data) for systems of
common interest. Information for the bond lengths, coordination numbers, strain defects etc
can be extracted from those models and used in your computations of band
structure/physico-chemical properties.
What do you think ? If you a positive I may check with NSF about funding opportunities. As a
beginning we may start with something simple, and see how it goes - Valeri
Dr. V. Petkov, Prof.
Department of Physics
203 Dow Science
FAX: (989) 774 2697
Phone: (989) 774 3395
E-mail: petkov@phy.cmich.edu
Central Michigan University, Mt. Pleasant, MI 48859, USA
Progress in Solid State Chemistry
Subramanian, Mas - COS [Mas.Subramanian@oregonstate.edu]
You replied on 6/9/2010 11:36 PM.
Sent:
Wednesday, June 09, 2010 8:23 PM
To:
Sun Changqing (Dr)
Dear Chang
I am writing to you regarding the journal Progress in Solid State Chemistry. Few years back you contributed
journal. We are looking for interesting articles for future issues. If you or you could suggest some prospectiv
contribute to the journal, I really appreciate it. If you already have some review article which you are interes
would be happy to consider it.
Thank you, Regards, Mas

I’m writing to you as the author of the important article “Thermo-mechanical behavior of
low-dimensional systems: The local bond average approach”, published in Progress in
Sun CQ/EEE
42
Materials Science earlier this year.
We are very interested in your agenda-setting Nanoscale research, and on behalf of the
three joint Editors-in-Chief (Professor Markus Niederberger - ETH Zurich, Professor
Francesco Stellacci - MIT, and Professor Chunli Bai - NCNST, Beijing) I would like to
invite you to submit a follow-up article to the exciting new journal Nanoscale, covering
recent progress and future directions in this area. We feel that such a high-profile feature
article (either an original research or review-type article) by you in this area would be
very topical and ideally suited to the journal.
Dr Philip Earis, Managing Editor of Nanoscale, 14/10/2009

I have read your review paper in solid state chemistry and lecture many parts of that to
my students. I have two MSc students working on nanosolid melting, sharing with nice
comments of Dr Barber from Cambridge University. It is a honor for me to invite you to
our team, pursuing this subject if possible.
Sohrab Sanjabi [sanjabi@modares.ac.ir]

I have been following some of your work on the origins of surface stresses for some time
now and I have found them to be especially illuminating. Much of my interest in the area
of interface and surface stresses has been on elucidating their consequences in
modifying the mechanical response of materials, for example, in modifying the tensile
response of nanowires. Your recent paper on the temperature dependence is particularly
interesting. I have always wondered if nanostructures such as nanowires would be
expected to show much stronger temperature dependence of stiffness than bulk
materials because of the added effect due to surface stresses. Perhaps that is a nice
problem worth pondering. Shankar, Ravi [shankarr@engr.pitt.edu]

We have read a number of your papers and found your theory very interesting. I think
you are right pointing out the difference in the crystallography of II-VI nanoclusters as
compared to the bulk respective materials.
Dr. Alexei Nabok

I am Mohammad Attarian Shandiz. I have published the paper "Effective coordination
number model for the size dependency of physical properties of nanocrystals". In this
paper, I have presented a new interpretation of your well-known theory, BOLS
correlation mechanisms, in terms of effective coordination number viewpoint. I really
appreciate your works and I am very happy of working on your theory. I really interested
to have more discussion on scientific topics especially size effect at nanoscale on
materials. Kind Regards, M A Shandiz

In our work on the C-C length and thickness, we used the equivalence between an
armonic potential with AMBER force field constants and strain energy of deep beams
with shear. The latter approach is the common one in structural mechanics approaches
to model CNTs like truss structures. The approach on your paper is rigorous, however
considers the quantization of measurable mechanical quantities as shell structures.
Shells have different axial, bending and membrane responses compared to truss-like
structures. It would be interesting to apply your model to a truss-like component for
further developments. There may be some scope on working together on this if you think
it is interesting. My sincere compliments also for your excellent website and the work of
Sun CQ/EEE
43
your Group. I noticed also your activities on dimer vibration. We have started to work on
systems of dimers for possible auxetics. Other works in dimer and trimer assemblies will
be presented at the Auxetics Conference in Bristol (14-17 September). I may contact you
in the future for similar topics, if that is something interesting to you.
Regards, Fabrizio

I found your paper list is very great and interesting.
Best regards, Prof. R.A.Andrievski; mailto:ara@icp.ac.ru

I searched and studied some of your paper about relation of binding energy to particle
size and so on. Your papers were very interesting for me but because my field is
chemistry, I couldn’t understand exactly your theory. I want to use this theory to explain
the observed blue shift in nano samples (XPS results), but I don’t know how I can use
the formula. I will appreciate any suggestion from you.
Nilofar Asim

Your recent paper on the temperature dependence is particularly interesting. I have
always wondered if nanostructures such as nanowires would be expected to show much
stronger temperature dependence of stiffness than bulk materials because of the added
effect due to surface stresses. Perhaps that is a nice problem worth pondering.
Shankar, Ravi [shankarr@engr.pitt.edu]

You have given me some very exciting and heavy reading which is mostly along the lines
of my recent text book: http://www.rsc.org/Publishing/Books/085404857X.asp. I think I
need to write a new edition quickly to account for your impressive work. I regret that I
was completely unaware of your work and the BOLS approach. I have however included
some of it in my current lecture course at the University. I hope we will get a chance to
meet at some point. Yours, Emil Roduner (e.roduner@ipc.uni-stuttgart.de]

I work as the Chief of Physics Department in Siberian State University of Industry. The
field of my scientific interest is connected with the nanostructures, nanomaterials,
nanotubes, behavior in an external energy influences (stresses, deformations,
temperatures, electromagnetic fields and so on).
Would you be so kind as to send me your article "Impact of bond-order loss on surface
and nanosolid magnetism" published in "Acta Materialia, 53 (2005), 3207-3214" and
similar ones. I can assure you I'll be most grateful to you. Your article will help us in our
scientific work.
With the best wishes
Sincerely yours, V.Gromov, e-mail: gromov@physics.sibsiu.ru

I recently read two review articles that you have posted on arXiv.org:
(1) Mechanical strength of atomic chains, surface skins, and nanograins
(2) Size and confinement effect on nanostructures
Congratulations on a job done well!. They are very instructive and should be a useful
reference for all of us.
Pradeep Sharma, Ph.D., Ch. Phy.
University of Houston
Sun CQ/EEE
44

I want to associate with you and built my carrier in this field, because till date there is no
any theoretical as well as experimental validity of phase transition in nanostructured
materials. Just went through all of yours papers, they are really excellent. Please accept
our warmest congratulations on such type of papers which give new dimensions of
research in the field of Nanotechnology.
- S.K.S.Parashar, Department of Physics and Meteorology
INDIAN INSTITUTE OF TECHNOLOGY KHARAGPUR 721 302, INDIA
E-mail : parashar@phy.iitkgp.ernet.in

It is refreshing to see how far the progress has been made in understanding size
dependent melting process since I did some work on the issue about ten years ago. I
want to congratulate you on your work.
--Frank Shi, University of California Irvine (fgshi@uci.edu)

We are organizing an international conf on nano sci and tech in delhi in march 16 to 18
2006. Looking at the massive amount of good quality work you and your group have
done, I would like to invite you to give a talk. I am interested in having a collaboration
with your group - let us then we can talk about it more. With best wishes,
Dr B. R. Metha, Physics, IIT, India

Thank you very much for sending me your latest paper. Your powerful theory about the
structure of nanosolid can be used to explain many novel phenomena in nanotechnology.
I explained the microstructure of metal and alloy nanoparticles mainly using your theory.
I am planning to do something on high frequency magnetic properties of nanomaterial.
The microstructure influences these properties greatly. So I will go on learning from you
in this field. Qin Yong

I have read with interest of your articles on nanostructures. I wonder if you have any
proper materials for teaching (Master Degree standard) on the related topics. IF it is
available please could you send me an attachment? Suddenly I have been asked to
teach this portion to our M.E. students. So I was wondering whether you have any idea
about the teaching materials. I shall be grateful if you could arrange and send an
attachment to me.
Prof. CK Sarkar, Department of Electronics and Tele-commun. Engg., Jadavpur
University, Calcutta 700 032, India

I believe that we have a lot of challenging scientific problems that will interest you. These
problems are ones that can result (when combined with on-going experimental work) in
publications in Nature and Science, where we have a good track record of publishing. I
would be very happy if you could arrange a visit to us and the longer you can stay the
better!
Best regards, Ray Baughman, TD NanoTech Institute, University of Texas at Dallas,
Dallas

I read with high interest your paper on the extended quantum confinement theory and I
wonder if I may visit you during my next stay at Singapore. This may be a good
opportunity to have a discussion. You might be also interested in some aspects of the
mechanical properties of superhard nanocomposites.
Sun CQ/EEE
45
Stan Veprek, Technical University Munich Lichtenbergstr. 4 D-85747 Garching b. Munich

Your model is very reasonable. It describes well a DECREASE of the Curie temperature
in VERY THIN films where the surface atomic energy modified by CN-imperfection is
comparable to the total energy of the film. I suppose it would describe also a decrease of
Tc of very thin superconducting films. Best wishes, Alexej

I've read your paper ‘Photoluminescence of Si Nanosolids near the Lower End of the
Size Limit (J. Physics. Chem. B 106, 11725 (2002)' that has thoroughly solved the great
difficulty faced by the QC model - the blue shift of PL peak energy is much lower than
predicted. I believe that your BOLS is the most successful and powerful one among the
available models.
Ran Guangzhao, School of PHYSICS, Peking Univ., Beijing 100871, China (Jul 01, 2003)

You have two more outstanding papers under review. I will follow them up accordingly.
You have done exceedingly well. I trust you must have a very future. Les Holland, Editor
for Vacuum, 1997

To Prof Bai Chunli (General sectary of STM’93 international conference): Chang has
made substantial progress towards a long-lasting problem of oxygen chemisorption since
joining in this July. He proposed a model of chemical bond and a model of threedimensional surface potential barrier that not only work well in decoding the VLEED data
we collected previously but also provide deeper insight into the mechanism behind. His
model can also found applications in other areas such as high Tc superconductivity of
metal oxide and amplify the capability of STM, AES and LEED in surface science. I am
pleased recommend him attend the STM’93 conference.
Dr Steven Thurgate (Sept 22, 1997).
3. Editor’s choice
From: Erica Wise [mailto:wisee@rsc.org]
Sent: Thursday, March 01, 2012 10:13 PM
To: Sun Changqing (Dr)
Subject: Chemical Science - manuscript ID C2SC20066J
C2SC20066J – The hidden force opposing ice compression
Dear Dr Sun,
I am writing a short news article on your above paper which will appear online on the
Chemistry World news page shortly (http://www.rsc.org/chemistryworld/). Some of the news
articles on the website will also be published in print as part of the Research section of
Chemistry World. I would be interested to hear from you about your work and use your
comments as quotes in the news piece. I have included a short list of questions below and
would be very grateful if you could send me your response to them as well as any general
comments/background information preferably by Monday.
Erica Wise
Sun CQ/EEE
46
Dr Erica Wise MRSC
Publishing Editor, Physical Chemistry Chemical Physics
Royal Society of Chemistry, Thomas Graham House,
Science Park, Cambridge CB4 0WF.
Tel: (+44) (0)1223 432184 & Fax: (+44) (0)1223 420247
From: projectprospect@rsc.org [mailto:projectprospect@rsc.org]
Sent: Wednesday, March 17, 2010 7:46 PM
To: Sun Changqing (Dr)
CC: Sun Changqing (Dr)
Subject: B9NR00326F - Your Nanoscale article has been Prospected
Dear Dr Chang Qing Sun
Paper Ref : B9NR00326F - Nanoscale
Local structure relaxation, quantum trap depression, and valence charge polarization
induced by the shorter-and-stronger bonds between under-coordinated atoms in gold
nanostructures
I’m pleased to inform you that we have selected your article (mentioned above) for enriched
html, as part of the RSC Project Prospect. If your institution is a subscriber, you can access
the enhanced version of your article using the following link:
http://xlink.rsc.org/?doi=B9NR00326F - if you have access do please look at the
enhancements.
Richard Kidd
Manager, Informatics
Royal Society of Chemistry, Thomas Graham House,
Science Park, Cambridge, CB4 0WF, UK
E-mail: projectprospect@rsc.org
Website: http://www.rsc.org and http://www.chemsoc.org
4. PhD Thesis
Report -1
Mr. Sun's doctoral thesis deals with a very important area of surface physics - the oxygenmetal surface interaction process. To provide insight into this area of research he has made
a detailed theoretical/empirical study of the O-Cu(001) system. The exact interaction
processes, including surface structural changes, for the O-Cu(001) system have been
unresolved for almost 20 years but Mr. Sun, using excellent VLEED and STM/S
experimental data provided by the Murdoch group for comparison purposes, appears to
have made a significant contribution to our knowledge for this system, and he has
formulated structural bond models for the different oxygen adsorption regimes, including
models for other oxygen-metal systems, a non-uniform potential barrier model and has
shown through computation that his modelling, based on good theoretical analysis of
previously published data provides excellent agreement with published experimental data,
and in particular, has provided a quantitative description of the reaction dynamics by
simulating different VLEED spectra.
Sun CQ/EEE
47
Overall, the thesis appears to have at last provided us with an understanding of the OCu(001) system and extension of this work to other oxygen-metal surface systems would not
only provide a further excellent research program but would confirm generalisation of the
approach taken.
The work presented in this thesis appears to be worthy of a PhD. However, I have had to
read the thesis a number of times to appreciate Mr. Sun's contribution and I am satisfied that
he has made significant contribution to our scientific knowledge. I do feel however, that the
thesis itself needs editing and correcting to such an extent that the process would be more
substantial than 'minor amendments'.
Report - 2
In this PhD thesis, Mr Sun aims at characterising the metal-oxygen bond structure by
proposing a bond-structure model, which goes beyond the ones published in the literature in
some aspects. The model focus more on bond formation and its consequences for
reconstruction etc. than just on a description of static atomic positions. In addition, Mr Sun
provides model calculations of a three-dimensional surface potential barrier to explain
STM/S results and VLEED data of oxygen adsorption on metal surfaces in a detailed
way. Mr Sun's is based on a very careful and comprehensive study of the literature. The
most important input for his work are other people's experimental results. From the title of
the thesis one may mislead that Mr Sun did modelling and experiment, but in the text he
always makes reference to the people who did the experimental work.
In the introductory first chapter, Mr Sun reviews the experimental and theoretical research on
oxygen-copper systems with respect to bond structure, STM/S and VLEED data. In the more
theoretical second chapter, he motivates his bond-structure model of oxygen-metal
chemisorption and proposes his models for bond structure and surface potential barrier. The
bond structure model is not only good for the specific O-Cu(001) system, but is successfully
applied to other systems as well. In addition, he describes his approach to calculate VLEED
spectra, which uses a code of Dr. Thurgate (Murdoch University). The third chapter is
dedicated to results and discussion. In much depth, where the reader - at some points tends to lose track, Mr Sun presents comparisons between experimental and calculated
spectra with the intention to learn more about the bonding structure and, in particular, the
bonding dynamics. Therefore, he models VLEED spectra taken at different oxygen
exposures, ie. at different oxidation stages. In chapter 4, the conclusion, Mr Sun discusses
the significance and the limitations of his work. It should be noted with appreciation that he
always makes very clear not only the achievements, but also the constraints of his models.
Mr Sun makes distinctive contribution to the knowledge of the oxygen-metal bonding by
proposing his model and using VLEED, STM/S data to develop a three-dimensional surface
barrier potential model describing all experimental results available to date. Mr Sun has not
performed experiments, nor has he done calculations from first principles, he rather bridges
the gap between experimentalists and theoreticians by developing models that try to
describe nature by searching for the relevant parameters. The results of this thesis may not
lead to a breakthrough in materials sciences to prevent corrosion, but they provide a deeper
understanding of the bonding dynamics and the relevant parameters responsible for it. A
considerable part of the thesis is written in a textbook style reviewing other people's work in
a detailed way, which is exemplary for any thesis. This provides an excellent over view of
the research done to date, on the other hand it blows up the volume of the thesis. Since the
thesis contains more than 240 pages, it is not always easy to extract the novel results of Mr
Sun. However Mr Sun successfully tried to overcome the problem by little summaries at the
end of chapters or subchapters to help the readers to not lose track. The thesis is well
structured and written clearly, the number of printing errors is small.
Sun CQ/EEE
48
In conclusion, I recommend that Mr Sun be awarded the degree of Doctor of Philosophy
without further examination.
Report -3
This thesis by Chang Qing Sun presents new works on the determination of the surface
barrier potential and the surface atomic structure of oxygen chemisorbed on copper (001). It
clearly demonstrates a significant contribution to our knowledge on the surface potential
barrier in general and on the Cu(001)-O system in particular. Although there have been
several studies of the atomic structure of oxygen on Cu(001) in the literature, which the
candidate critically reviews in the thesis, there remains some doubt as to the exact structure
of the Cu(001)-O system. The candidate presents a well argued case, making appropriate
use of and reference to experimental observations from related structures, for his bondstructure model based on a quasi-tetrahedral structure of the sp3-type hybridised
oxygen. By proposing a model in this way the number of parameters needed is reduced and
subsequent optimisation of the structure using very low energy electron diffraction (VLEED)
data is simplified. In addition to the structure determination, the surface potential barrier
(SPB) is determined, using a paramerised set of empirically derived functions for the
dependence of quantities on z (the distance perpendicular to the surface of the
crystal). Both a uniform barrier in x & y, and a 3-dimensional nonuniform barrier are
considered. The parameters of the two types of barriers are fitted to experimental data, in
particular, STM images of the O-Cu(001) surface acquired by others, and results show a
considerable improvement in agreement between VLEED I-V theory and experiment when
the 3-D non-uniform SPB is used. The work presented in this thesis on the surface potential
barrier represents, as far as I'm aware, the current state-of-the-art determination for an
oxygen adsorbate - metal system.
The candidate presents a critical appraisal of his results and discusses them in the light of
existing models and experimental data. The sensitivities of the level of fit to variation in the
structural and barrier parameters are investigated. This enables the changes in the VLEED IV data which occur on further oxygen exposure of the surface to be interpreted and
quantified in terms of distinct displacements in the atomic positions of the atoms in the
surface. Thus providing insight into the physical and chemical processes which take place
with increasing oxygen exposure of the Cu(001) surface.
One clear question that is not explicitly addressed by the candidate, but is largely implicitly
answered by the approach taken, is: are there too many parameters (structural and barrier
related) which are involved in optimising the fit of theory to the relatively small set of
experimental data? By the appropriate use of a structural model and exploiting correlations
in the parameters of the barrier, the candidate reduces the initially large set of parameters to
a more reasonable number and discusses the issue of uniqueness of the solution
found. However, it would seem to me that z0(E) and the surface atomic structure must be
related to some extent, but it is unclear from the work presented in the thesis what is the
strength of this relation or how it may affect the results.
The concluding chapter is quite well-balanced presenting the candidate's view of the
achievements of the thesis work, and, importantly, highlighting limitations and assumptions
in the methodology used. The candidate very usefully set out a number of objectives in
section 1.5, it would have been a useful exercise in this concluding chapter to have
specifically answered each objective in the light of the work that had been done. It is also of
value if some discussion is presented of the future work which may benefit from the
knowledge gained in the thesis work.
Overall, the thesis is of high scientific standard and has demonstrated many original
contributions to knowledge. I recommend Chang Qing Sun be awarded a PhD degree.
Sun CQ/EEE
49