Chemistry Reference
In-Depth Information
Table 7
Calculated stabilization energies [kcal
/
mol] of the XY
···
NH
3
complexesasob-
tained with different methods applying the aug-cc-pVTZ basis set
XY
MP2
CCSD(T)
B3LYP
BH&HLYP
Refs.
F
2
∆
E
-2.0
-2.0
-4.6
-1.2
[26]
∆
E
CP
-1.8
-1.7
-4.5
-1.2
ClF
∆
E
- 11.8
- 10.1
- 12.6
- 9.7
[26, 28]
∆
E
CP
- 11.0
- 9.4
- 12.4
- 9.5
Cl
2
∆
E
-5.5
-4.9
-5.9
-4.2
[26]
∆
E
CP
-4.9
-4.4
-5.8
-4.1
BrF
∆
E
- 16.8
- 15.0
- 15.8
- 13.8
∆
E
CP
- 14.6
- 13.2
- 15.6
- 13.6
BrCl
∆
E
- 10.1
- 9.0
- 9.5
- 7.6
∆
E
CP
-8.5
-9.4
-7.5
Br
2
∆
E
-8.6
-7.6
-5.9
∆
E
CP
-6.9
-7.5
-5.8
corrected CCSD(T) stabilization energies of the XY
···
NH
3
complexes range
from -1.7 kcal
mol for BrF-NH
3
.This
range is also typical for weak to medium strong hydrogen bonds. The dif-
ferences between
/
mol for F
2
-NH
3
to about -13 kcal
/
E
CP
, as evaluated with MP2 and CCSD(T), are
very systematic. Apart from F
2
∆
E
and
∆
NH
3
, the agreement between CCSD(T) and
BH&HLYP is again excellent. The interaction strength increases in the series
of X
2
···
···
NH
3
in the order F
2
,Cl
2
,andBr
2
, as dictated by the trends in po-
larizabilities, and in the series of XY
···
NH
3
in the order ClF, BrCl, and BrF,
Table 8
Calculated dipole moments (
µ
)[D]anddipolemomentenhancements(
∆
µ
)rela-
tive to monomers of the XY-NH
3
complexesasobtainedwithdifferentmethodsapplying
the aug-cc-pVTZ basis set
XY
MP2
B3LYP
BH&HLYP
Refs.
F
2
µ
1.99
4.57
1.95
[26]
∆
µ
0.47
3.08
0.44
ClF
µ
5.68
5.98
5.10
[26, 28]
∆
µ
2.50
2.80
1.97
Cl
2
µ
3.40
4.41
3.26
[26]
∆
µ
1.88
2.92
1.65
BrF
µ
6.48
6.64
6.19
∆
µ
3.68
3.67
3.27
BrCl
µ
5.23
5.77
4.93
∆
µ
3.26
3.79
2.96
Br
2
µ
4.59
5.16
4.22
∆
µ
3.07
3.67
2.57
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