Chapter 4
Theoretical Prediction of A New Class of Xenon Containing
Molecules and Anions NXeOnFm
Abstract
We have predicted a new series of xenon containing noble-gas molecules. These
molecules consist of xenon, nitrogen, oxygen and fluorine atoms with the general
formula of NXeOnFm and NXeOnFm, for example: NXeOF3 , NXeF3 , NXeF5 ,
NXeOF2, NXeO2F2 , NXeOF4 and NXeF4. The best estimates of the atomization
energies of the most stable species NXeF5 and NXeOF4 were 104 and 140 kcal/mol,
respectively. These are higher than those of XeNO2 and XeNO3 in our previous
study by ~50 kcal/mol. These molecules were all predicted to have very short XeN
bond lengths (~1.8 Å), suggesting XeN triple bonds. The lowest unimolecular
dissociation barriers of the most stable species NXeOF4 were estimated to be
33 kcal/mol. Many of these molecules and anions were predicted to be kinetically
stable at low temperature.
107
Introduction
Traditionally, noble gases were found to be extremely stable and were difficult to
form molecules with other elements. However, since the first Xe compound XePtF6
had been synthesized in 1862 by Bartlett et al,1 a large variety of noble gases
containing compounds, mostly containing Xe, F, and O atoms. have been found in
various laboratories,.2,3 Recently, Räsänen and coworkers4 have found many xenon
containing molecules of the type HXeY (where Y is usually an electronegative group
such as Cl, Br, I, OH, CN, NC, CCH, SH, NCO, etc.) using matrix
isolation/photolysis techniques. Xenon is also known to play the role of ligands to
transition-metal ions and to form actinide complexes with the CUO molecule.5 The
first compound that contains the XeN bond, FXeN(SO2F)2, was synthesized in 1974
by LeBlond and DesMarteau.6 About twenty other compounds containing XeN bond
had been synthesized in the experiment during the next 25 years.7 The study on the
XeN compounds was notbly followed by Schrobilgen and coworkers in recent years.
8,9 In
our previous theoretical studied,10 the XeNO2 and XeNO3 anions had been
predicted to be stable with 50 and 101 kcal/mol atomization energies and very short
XeN bond lengths (~1.8 Å). We have been wondering if there are any other types of
stable molecules or anions also containing the XeN triple bond motif. From past
experience, stable Xe compounds are chemically bonded to fluorine or oxygen
atoms.11 Therefore, in this research, we tried to replace one or more oxygen atoms in
XeNO2 and XeNO3 with fluorine atoms to generate a new series of neutral and
mono-negative charged species such as NXeO2F and NXeOF4. The molecules and
anions we tested can be expressed as NXeOnFm or NXeOnFm. For Xe atom, at most
8 valance electrons can be shared to surrounding electronegative atoms. For example,
108
in XeNO3, 3 valence electrons of Xe are shared with the N atom and 6 valence
electrons were shared with three O atoms, and the negative charge is delocalized
within the entire molecule. Thus the combinations we tested were n=1-2 and m=1-4
for NXeOnFm or NXeOnFm. The negative charge keeps the molecules with even
electrons. Species with some of the combinations were found be unstable. The stable
(with atomization of at least 30 kcal/mol) neutral and mono-negative charged species
we founded were NXeOF3 , NXeF3 , NXeF5 , NXeO2F2 , NXeOF4 , NXeOF2 and
NXeF4. Some isoelectronic neutral molecules without N atom, such as XeO3F2,
XeO2F4, XeO2F2 and XeOF4 were also compared in this study.
109
Method
The molecular geometry was calculated using the MP212 and CCSD(T)13 theory
and the hybrid density functional theory B3LYP14 and MPW1PW9115 with the
aug-cc-pVTZ basis sets for N, O and F atoms.16 For Xe atoms, the aug-cc-pVTZ-pp
basis sets was used. The “pp” means that a pseudo-potential was used to replace the
core electrons. Our previous study10 showed that the B3LYP method with
aug-cc-pVTZ(-pp) basis sets predicted structures and energies in reasonable
agreement with the higher level coupled cluster method. Single-point energy
calculation was also performed at CCSD(T)/aug-cc-pVTZ(-pp) level using the B3LYP
geometry. For brevity, the basis sets will just be described as aug-cc-pVTZ for the rest
of this article, and they are abbreviated as apnz in all the Tables. All calculations were
performed using the Gaussian 03 program.17
110
Result and Discussion
(a) Geometry
In our previous study, the bonding between xenon and nitrogen atoms of XeNO2
and XeNO3 could be assigned as a triple bond. Three valence electrons of xenon are
shared with the nitrogen atom. Bases on the Lewis structure, there are five other
valence electrons of xenon can be shared with other oxygen and fluorine atoms. Thus,
the possible NXeOnFm molecules with even numbers of electrons are NXeF, NXeOF,
NXeO2F, NXeF3, NXeOF3, NXeF5, NXeO, NXeF2, NXeOF2, NXeO2F2 and
NXeF4. However, the NXeF, NXeOF, NXeO2F and NXeO were found to have
very small (less than 30 kcal/mol) atomization energies at B3LYP/aug-cc-pVTZ level.
Therefore, these molecules will not be further discussed in this study.
Figure 1 shows the calculated structures of NXeF3, NXeOF3, NXeF5, NXeF2,
NXeOF2, NXeO2F2 and NXeF4. The structure of XeNO3 was also showed in
Figure 1 for comparison. The calculated vibrational frequencies are listed in the Table
1. The calculated frequencies of XeN stretching mode are predicted to be 866~965
cm-1 at B3LYP/aug-cc-pVTZ level. Those were slightly higher than the XeN
stretching frequency of the XeNO3 of 848 cm-1 calculated at the same level of
theory. Table 2 shows the calculated XeN bond lengths at various theoretical levels.
The NXeF4 was predicted with the shortest XeN bond of 1.757 Å at
B3LYP/aug-cc-pVTZ level. At CCSD(T)/aug-cc-pVTZ level, the XeN bond length
of NXeF4 is 1.754 Å which is significantly shorter than the predicted length of 1.800
Å in XeNO3 of.ref. The XeN bond lengths of NXeF5 and NXeF4 in Table 2, also
111
show that the B3LYP/aug-cc-pVTZ method predicted XeN bond lengths in better
agreement with the higher level CCSD(T)/aug-cc-pVTZ method than the
MPW1PW91 and MP2 methods. The calculated XeN bond length at
B3LYP/aug-cc-pVTZ level in Table 2 were all in the range of 1.757~1.792 Å, and, as
discussed in our previous study, bonding could be assigned as triple bonds.
The XeO and XeF bond length of these molecules were also shown in Figure
1. The XeF bond length predicted by B3LYP/aug-cc-pVTZ were 1.902~2.095 Å,
which can be compared with the experimental XeF bond lengths of 1.974 Å .18 The
two types of XeF bond lengths of NXeF5 were predicted to be 1.906Å and 1.868Å at
the CCSD(T)/aug-cc-pVTZ level. For comparison, the bond length of XeF6 (Oh) was
1.942 Å at the same level, which was in good agreement with experimental value of
1.941 Å18. The B3LYP/aug-cc-pVTZ calculation predicted that the XeN bond is
shorter than XeO bond by approximately 0.02~0.03 Å for anions. This is consistent
with our previous study on XeNO2 and XeNO3. However, the XeN bond is
slightly longer than XeO bond in the neutral molecule NXeOF3 by 0.003 Å.
(b) Thermodynamic stability
Table 3 shows the relative energies to the most stable atomic species of the
molecules in this study at various theoretical levels. These energies can also be
described as the total atomization energies (TAE) of the molecules. The NXeF5 ,
NXeOF4 , and NXeF4were found to have the highest TAE of ~104, 140, and 134
kcal/mol at CCSD(T)/aug-cc-pVTZ level, respectively. Table 3 also shows the TAEs
obtained by the CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ calculations
(CCSD(T)/aug-cc-pVTZ single point calculations using the B3LYP/aug-cc-pVTZ
112
structures) were very close to the CCSD(T)/aug-cc-pVTZ values for the NXeF5 and
NXeF4. The TAEs listed in Table 3 are 57.5~139.7 kcal/mol at
CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ level. In comparison, the atomization
energy of XeNO2 and XeNO3 were 40.9 and 87.0 kcal/mol at the
CCSD(T)/aug-cc-pVTZ level.
The calculated triplet state energies relative to the ground singlet state (using the
singlet structure) at various theoretical levels are listed in Table 4. At the singlet
structures, the triplet states were 28.7~103.2 kcal/mol higher in energy at
CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ level, and thus the calculated singlet
state is the ground electronic state. The spin-orbital coupling could certainly have
some effects on the ST gaps, relative energies, and molecular geometry. However,
according to our pervious study, the typical spin-orbital energies of these species are
on the order of 1 kcal/mol or less. Thus, to a good approximation, the spin-orbital
coupling would not affect the calculated results significantly.
(c) kinetic stability
The possible unimolecular dissociation products on the singlet-state surface and
their relative energies for the unimolecular dissociation channels at various theoretical
levels are listed in Table 5. For the very endoergic unimolecular dissociation channels,
the barriers were less important. For the exoergic unimolecular dissociation channels
on the singlet-state surface, at least one transition state has been found for these
molecules. The calculated barrier heights for these channels were also listed in Table 5.
The transition state structures calculated by B3LYP/aug-cc-pVTZ method of these
molecules were showed in Figure 3. The lowest unimolecular dissociation barriers of
three neutral molecules NXeOF3, NXeF3 and NXeF5 were found be 15~21 kcal/mol
113
at the same level which were significantly lower than those of the XeNO2 or
XeNO3( ~40 kcal/mol at CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVDZ level).
However, the dissociation barriers of the three anions NXeOF2, NXeO2F2 and
NXeOF4 were significantly higher(26.0~36.2 kcal/mol).
The TS of NXeOF4of the dissociation channel to XeF4 + NO(S) was not be
found. However, the barrier of another similar dissociation channel NXeOF2 
XeF2 + NO(S) was calculated to be 26.0 kcal/mol at
CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ level. Thus, we believe that the
dissociation barriers of NXeOF4 XeF4 + NO(S) would be quite similar if the TS
exists. The barrier for the NXeF4dissociation to XeF3 + NF was predicted to be
27.3 kcal/mol, and this is an endoergic reaction by 19.7 kcal/mol. The only two
exoergic unimolecular dissociation channels of NXeF4are reactions to XeF2 + NF2
and XeF + NF3. These two channels are unlikely to proceed by a concerted step
(these would require breaking at least three bonds at the same time), and should
involve very high barriers. On the other hand, the barrier of NXeF4  XeF3 + NF
is 27.3 kcal/mol. This channel was involved with breaking only one XeF and one
XeN bond. That is, we believe the dissociation barriers of NXeF4 into XeF2 +
NF2 and XeF + NF3 will be significantly higher. The dissociation of NXeF4 to
NXeF3 + F is endoergic by 76 kcal/mol, which indicates a very strong interaction
between the neutral NXeF3 molecule and the fluoride ion.
In our previous study,19 we have established a relationship between the stability
114
and the dissociation barrier heights for noble gas molecules. In order to have a
half-life of ~102 seconds for spectroscopic study in the gas phase at 100, 200 and 300
K, the noble gas molecule with neighboring heavy atoms must at least have
barriers
of 9, 17, 25 kcal/mol respectively. Thus, these mono-negative charged species were
predicted to be kinetically stable below 300 K, and the neutral molecules will be
stable below 100K.
(d) isoelectronic molecules
Several isoelectronic molecules of NXeO2F2 , NXeOF4 , NXeOF2 and
NXeF4 were also investigated in the current study. By replacing the N with an O
atom, these molecules were XeO2F2, XeO3F2, XeO2F4 and XeOF4. The calculated
structures of XeO2F2, XeO3F2, XeO2F4 and XeOF4, are depicted in Figure 3. At
B3LYP/aug-cc-pVTZ level, the XeF and XO bonds in these molecules are all
slightly shorter than their isoelectronic anions. For example, the XeF and XO bond
lengths of XeO2F4 are 1.903 Å and 1.764 Å, respectively, which are 2.020 Å and
1.797 Å in NXeOF4.
The total atomization energies (TAE) of these molecules were listed in Table 6,
which were predicted to be ~20 kcal/mol higher than their isoelectronic anions. For
example, the TAE of XeO2F4 and NXeOF4 are 158.9 and 139.7 kcal/mol,
respectively at CCSD(T)/aptz//B3LYP/aptz level. This result was actually expected
since the XeO bond could be slightly stronger than the XeN bond, as we
discovered in the difference of TAE for XeNO2 and XeO3 in our previous study10.
115
Conclusions
In the current study, we have predicted a new series of xenon containing
noble-gas molecules, in particular, NXeOF3 , NXeF3 , NXeF5 , NXeOF2,
NXeO2F2 , NXeOF4 and NXeF4. These molecules or anions showed strong
bonding between xenon and nitrogen atoms with very short bond distances. Based on
the calculated structures and the Lewis structures, these XeN bonding can be
tentatively assigned as triple bonds. The total atomization energies (TAE) of the
molecules are all higher than 50 kcal/mol, and the dissociation barriers are higher than
15 kcal/mol. These molecules were predicted to be stable at cryogenic condition, and
could be targets of future experimental identification.
This study showed that
species obtained by replacing the oxygen atoms with fluorine atoms from NXeO2 or
NXeO3 can also be stable. Thus it is also possible that other types of noble gas
molecules or anions obtained by replacing the fluorine by other monovalent
functional groups, such as CH3, C2H5, OH, Cl, NO2, etc., might also be stable at
cryogenic conditions. In addition, the N and O atoms on NXeO2 or NXeO3 might
also be able to bond to other atoms and form ring-type Xe molecules or even
Xe-containing polymers.
116
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119
Table 1. The calculated frequencies at B3LYP/aug-cc-pVTZ level of several
molecules in this study
(a) NXeOF3
mode
Frequencies (cm-1)
IR Intensity
NXeF scissoring
OXeF and FXeF scissoring
NXeO and FXeF scissoring
FXeN wagging
N wagging
132.6
159.9
234.2
283.8
294.1
0.6
0.0
8.9
2.7
1.8
OXeF and FXeF scissoring
O wagging
294.1
333.8
493.1
534.1
560.4
796.8
883.2
24.0
6.1
3.5
101.8
218.0
26.5
8.2
FXe asymmetric stretching
FXe symmetric stretching
FXe asymmetric stretching
OXe stretching
NXe stretching
120
(b) NXeF3
mode
Frequencies (cm-1)
IR Intensity
NXeF and FXeF scissoring
FXeF wagging
F wagging
N wagging
N wagging
FXe asymmetric stretching
FXe symmetric stretching
FXe asymmetric stretching
111.2
147.6
182.0
207.9
272.7
452.9
496.3
532.3
3.1
5.2
0.2
23.5
1.9
37.1
83.5
264.6
NXe stretching
934.6
3.3
irreducible representation (mode)
Frequencies (cm-1)
IR Intensity
E (FXeF wagging)
B2 (FXeF twisting)
B1 (FXeF scissoring)
E (N wagging)
167.1
222.5
229.6
271.4
0.0
0.0
0.0
1.8
A1 (FXeF wagging)
E (F wagging)
323.8
364.5
492.6
519.5
563.1
578.6
929.9
30.1
1.9
0.0
18.0
212.7
50.5
12.8
(c) NXeF5
B2 (FXe asymmetric stretching)
A1 (FXe asymmetric stretching)
E (FXe asymmetric stretching)
A1 (FXe stretching)
A1 (NXe stretching)
121
(d) NXeOF2
mode
Frequencies (cm-1)
IR Intensity
FXeF scissoring
FXeF wagging
NXeO and FXeF
twisting
117.5
138.1
17.4
18.4
193.0
0.6
NXeO wagging
NXeO scissoring
FXe symmetric stretching
FXe asymmetric stretching
222.7
286.5
354.4
390.4
0.1
28.9
35.3
318.7
OXe stretching
NXe stretching
733.1
901.9
91.0
55.6
irreducible representation (mode)
Frequencies (cm-1)
IR Intensity
A' (OXeO rocking)
A' (OXeF twisting)
A' (NXeF wagging)
A" (N wagging)
166.6
171.4
269.2
291.6
0.0
0.2
24.0
3.1
A' (OXeO scissoring)
A" (OXeO twisting)
A" (OXeO wagging)
A' (FXe symmetric stretching)
A" (FXe asymmetric stretching)
A' (OXe symmetric stretching)
A' (OXe asymmetric stretching)
A' (NXe stretching)
310.8
311.3
334.8
398.4
460.3
731.6
771.5
866.5
32.0
0.0
6.1
8.0
320.6
37.4
107.9
55.6
(e) NXeO2F2
122
(f)
NXeOF4
irreducible representation (mode)
Frequencies (cm-1)
IR Intensity
E (FXeF wagging)
B1 (FXeF scissoring)
B2 (FXeF twisting)
E (N wagging)
B2 (FXe asymmetric stretching)
A1 (FXe symmetric stretching)
123.0
173.0
216.0
307.5
308.8
356.8
390.5
442.6
0.1
0.0
0.0
3.1
27.3
2.0
0.0
13.7
E (FXe asymmetric stretching)
A1 (OXe asymmetric stretching)
A1 (NXe stretching)
484.2
737.9
866.4
309.2
27.5
30.1
irreducible representation (mode)
Frequencies (cm-1)
IR Intensity
B2 (FXeF twisting)
E (FXeF wagging)
115.5
126.2
161.4
0.0
0.3
0.0
194.1
257.0
351.5
432.4
447.2
965.4
36.1
0.5
0.0
40.5
327.9
20.0
A1 (FXeF wagging)
E (O wagging)
(g) NXeF4
B1 (FXeF scissoring)
A1 (FXeF wagging)
E (N wagging)
B2 (FXe asymmetric stretching)
A1 (FXe symmetric stretching)
E (FXe asymmetric stretching)
A1 (NXe stretching)
123
Table 2. Calculated Xe-N Bond Lengths (Å) of molecules in this study
B3LYP/apdz
B3LYP/aptz
MPW1PW91/apTZ
MP2/apTZ
NXeOF3
1.814
1.783
1.763
1.755
NXeF3
1.806
1.773
1.754
1.791
NXeF5
1.791
1.761
1.744
1.732
NXeOF2
1.823
1.792
1.773
1.772
NXeO2F2
1.818
1.79
1.771
1.76
NXeOF4
1.811
1.78
1.761
1.747
NXeF4
1.785
1.757
1.74
1.768
124
CCSD(T)/aptz
1.758
1.754
Table 3. Calculated Total Atomization Energies (kcal/mol) of the molecules in this study
B3LYP/apTZ
MPW1PW91/apTZ
MP2/apTZ
NXeOF3
33.5
60.5
53.7
102.8
63.8
NXeF3
43.8
60.8
51.6
96.5
57.5
NXeF5
69.4
99.2
92.7
149.3
NXeOF2
51.8
71.1
65.8
96.9
70.6
NXeO2F2
61.0
89.8
87.7
128.6
96.2
NXeOF4
108.1
136.4
132.0
179.3
139.7
NXeF4
121.9
139.7
132.0
174.0
125
CCSD(T)/aptz
CCSD(T)/aptz //
B3LYP/aptz
B3LYP/apDZ
104.8
134.3
103.7
133.8
Table 4. Calculated S-T gap (kcal/mol) of molecules in this study
S-T gap
B3LYP/apDZ
B3LYP/apTZ
MPW1PW91/apTZ
MP2/apTZ
CCSD(T)/aptz // B3LYP/aptz
NXeOF3
12.0
20.7
26.6
68.6
33.4
NXeF3
33.3
43.3
41.8
84.7
50.5
NXeF5
4.5
14.9
20.6
46.7
28.7
NXeOF2
47.1
55.4
60.8
86.7
64.3
NXeO2F2
30.5
38.4
45.1
65.0
50.4
NXeOF4
15.7
26.0
32.4
55.2
38.3
NXeF4
72.5
66.8
70.8
155.7
103.2
126
Table 5. The calculated relative energies (kcal/mol) and the transition states (TS) for
the unimolecular dissociation channels.
CCSD(T)/aptz //
B3LYP/aptz
MP2/aptz
B3LYP/aptz
NXeOF3
0.00
0.00
0.00
XeOF2 + NF(S)
44.67
12.16
33.10
TS
21.27
46.75
26.13
XeF3(D) + NO(D)
166.56
119.68
143.12
TS
9.73
37.33
14.74
NXeOF + F2(S)
20.33
36.84
23.31
NXeF3
0.00
0.00
0.00
XeF2 + NF(S)
41.80
7.28
35.53
TS
19.00
54.11
18.71
NXeF + F2
46.84
88.42
51.13
NXeF5
0.00
0.00
0.00
XeF4 + NF(S)
63.93
29.26
45.90
TS
16.74
53.19
20.96
NXeF3 + F2(S)
1.30
10.90
9.97
127
CCSD(T)/aptz //
B3LYP/apTZ
MP2/apTZ
B3LYP/aptz
NXeOF2
0.00
0.00
0.00
XeF2 + NO(S)
45.59
20.13
33.89
TS
48.30
49.98
26.04
XeOF + NF(S)
1.29
26.11
4.57
TS
22.82
52.20
24.40
NXeO + F2
101.14
120.02
99.01
NXeO2F2
0.00
0.00
0.00
XeOF2 + NO(S)
29.43
0.36
12.20
TS
31.90
57.02
36.21
XeO2F + NF(S)
3.38
28.05
7.43
TS
28.05
52.32
33.32
NXeF2 + O2(S)
24.06
7.43
0.54
NXeO2 + F2
62.92
74.48
64.78
NXeOF4
0.00
0.00
0.00
XeOF3 + NF(S)
31.36
1.06
19.18
TS
25.43
N/A
32.46
XeF4 + NO(S)
40.75
12.45
21.37
NXeOF2 + F2
28.27
40.56
32.87
NXeOF3 + F
75.9
76.5
75.9
128
CCSD(T)/aptz //
B3LYP/apTZ
MP2/apTZ
B3LYP/aptz
NXeF4
0.00
0.00
0.00
XeF3 + NF(S)
13.75
48.95
19.67
TS
25.59
N/A
27.34
XeF2 + NF2
21.54
12.05
13.24
XeF + NF3
73.16
45.43
69.63
NXeF2 + F2
73.43
94.16
73.98
XeF4 + N-(T)
91.21
123.87
99.11
NXeF3 + F
78.9
77.5
76.2
129
Table 6. Calculated Atomization Energies (kcal/mol) of XeO2F2, XeO3F2, XeO2F4 and XeOF4
B3LYP/apDZ
B3LYP/apTZ
MPW1PW91/apTZ
MP2/apTZ
CCSD(T)/aptz // B3LYP/aptz
XeO2F2
70.9
96.0
91.4
129.5
99.3
XeO3F2
69.0
103.6
101.1
152.4
114.6
XeO2F4
111.5
147.6
145.2
203.7
158.9
XeOF4
123.3
147.7
141.8
186.0
130
(a) NXeOF3 (CS symmetry)
(b) NXeF3 (CS symmetry)
(c) NXeF5 (C4v symmetry) (the CCSD(T)/aptz structure in parentheses)
131
132
(d) NXeOF2 (CS symmetry)
(e) NXeO2F2 (CS symmetry)
133
(f) NXeOF4 (C4v symmetry)
(g) NXeF4 (C4v symmetry) (the CCSD(T)/aptz structure in parentheses)
134
(h) XeNO3 (C3v symmetry) (CCSD(T)/aptz structure)
Figure 1. The calculated structures of NXeOF3, NXeF3, NXeF5, NXeF2, NXeOF2,
NXeO2F2, NXeF4 and XeNO3 at B3LYP/aug-cc-pVTZ level.
135
(a) XeO2F2
(b) XeO3F2
136
(c) XeO2F4
(d) XeOF4
Figure 2. Calculated structures of XeO3F2, XeO2F4, XeO2F2 and XeOF4 by
B3LYP/aug-cc-pVTZ method
137
(a) NXeOF3  XeF3(D) + NO(D)
(b) NXeOF3 XeOF2 + NF(S)
138
(c) NXeF3  XeF2 + NF(S)
(d) NXeF5  XeF4 + NF(S)
139
(e) NXeOF2 XeF2 + NO(S)
(f)
NXeOF2 XeOF + NF(S)
140
(g) NXeO2F2  XeOF2 + NO(S)
(h) NXeO2F2 XeO2F + NF(S)
141
(i)
NXeOF4 XeOF3 + NF(S)
(j)
NXeF4 XeF3 +NF(S)
Figure 3 Transition state structures calculated by B3LYP/aug-cc-pVTZ.
142