Bonding Electronics and Energetics (BEE) – Progress summary
If one bond breaks, the neighboring ones become
shorter and stronger, leading to strain and trapping
that causes localization and densification of charge,
energy, and mass in the relaxed surface skin whereas
atoms in the core interior remain as they are in the
bulk. Therefore, the broken bond matters the performance of nanostructures by modulating the atomic
cohesive energy, Hamiltonian, and elastic modulus,
giving rise to the bond-order-length-strength (BOLS)
correlation mechanism [1], which has enabled unification of the size dependency of nanostructures with
derived information such as the energy levels of an
isolated atom (see table) and the vibration frequency
of an isolated dimer.
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2.
Tab. BOLS derived energy levels of isolated atoms.
Energy Au-4f
Cu-2p Cu-3d Pd-3d
Si-2p
-Ec(∞) 84.37
932.70 7.23
334.35 99.20
-Ec(1)
81.50
931.00 5.51
330.34 96.74
140
MC Maximal Strain (%)
Broken bond matters nanosolid devices
Ir - MC
80
60
40
20
0.05
0.10
0.15
0.20
0.25
T/Tm,bulk
Fig. 1 BOLS correlation and the enabled reproduction of the
measured T-dependent strain limit of atomic chains.
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C2H2Cu3
Fig. 2 Cu3O2 and C2H2Cu3 bonding to the Cu(001) surface.
Fig. 3 BBB-derived media for blue light emission and diamond-metal adhesion.
--------------------------------------------------(a)
Local bond average approach
(b)
CdSe
-20
Pc (GPa)
4.0
3.5
3.0
-40
Data-1
Data-2
Data-3
Data-4
Data-5
Data-6
m=4.88,dot
m=4.88,rod
-60
-80
9
12
15
18
21
24
R (nm/10)
2
4
6
8
K (=D/2d)
Fig. 4 Pressure dependence of critical size for solid phase
transition at the ambient temperature, (b) size dependence
of Si dielectrics, and T-dependence of (c) Raman shift and
(d) elastic modulus of Si.
----------------------------------
Edge and interface quantum trapping
The combination of (1) and (2) leads to the intriguing
states in the edges, surfaces and interfaces. The
trapped and densified bonding states polarize the nonbonding and antibonding states, giving rise to the edge
states as observed from the edge of graphene ribbon
and the end of atomic chains; Charge and energy density gain in the junction interface provide a novel
mechanism of trapping in the quantum transport dynamics of phonons, electrons, and photons in nanosolid devices and mechanism for the interface dielectric
ferroelectric breaking, and mechanical strengthening
[5] .
A/Prof Chang Q Sun, FRSC, FInstP, FSNN
5.0
4.5
For a given specimen, the nature and the total number
of bonds remain unchanged before phase transition
yet the length and strength of the bonds response to
the external stimulus such as coordination environment, temperature, pressure, electric and magnetic
field, etc. One can thus focus on the representative
bonds or their average to approach the performance of
a solid in particular with the anisotropic, kinetic, and
localized nature. Reproduction of experimental observations has led to knowledge of single bond energy
and rule for the joint effect of pressure and size on
solid phase transition [4].
_______________________________________
4.
Au - MC
Pt - MC
100
O, N, and C tetra-bonding kinetics
O, N, and C atom forms tetrahedron with atoms in
solid phase, generating the bonding, nonbonding (lone
pair or unpair), antibonding (dipole), and H-bond like
states adding to the valence band of the host specimen,
which leads to the bond-band-barrier (BBB) correlation mechanism [2] and enabled STM/LEED quantification of four-stage Cu3O2 and C2H2Cu3 bonding kinetics and derivatives of new materials for blue light
emission, electron emission, and diamond-metal adhesion [3].
_____________________________________
3.
120
0
0.00
r suppression (%)
1.
1. Size dependence of nanostructures: Impact of bond
order deficiency. Prog Solid State Chem, 2007;35:1-159.
2. Oxidation electronics: bond-band-barrier correlation
and its applications. Prog Mater Sci, 2003;48:521-685.
3. Charge polarization and repopulation in tetrahedron
chemistry, in Chemical reaction on solid surfaces, F.
Columbus, 2007, ASP: New York.
4. Mesoscopic thermo-mechanics: Local bond average. In
press.
5. Atomistic origin, temperature dependence, and responsibilities of surface energetics: An extended brokenbond rule. Phys Rev B, 2007. 75(8): 085427.
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