bond lengths of monomers were kept frozen in their ground state geometry. We
have limited the expansion of induction part (3.1.9) and dispersion part 3.1.17 of
dipole moment to the terms *R
−4 through the terms *R
−7 . The results of analytical representation and ab initio calculations for selected angular orientations are
Table 3.1 Dipole moment of N 2 –N 2 dimer (in D)
Configuration
R e , Å
[115]
μ[115]
r 1 = r 2 = 2.08
a 0
μ
a
μ
b
μ
c
μ
d
μ
e
θ 1 θ 2 Φ
Gear-45
(C 2h )
45 45
0 4.09
0.000
0.000 0.000 0.000 0.000 0.000
Gear-30
(C s )
60 30
0 4.10
0.017
0.019 0.023 0.023 0.023 0.022
Gear-15
(C s )
75 15
0 4.13
0.030
0.032 0.039 0.038 0.038 0.037
T (C 2V )
90
0
0 4.15
0.034
0.036 0.044 0.043 0.043 0.042
X30 (C 1 ) 90 30 90 4.03
0.025
0.028 0.034 0.034 0.034 0.033
X60 (C 1 ) 90 60 90 3.78
0.001
0.011 0.014 0.014 0.014 0.014
X (D 2d )
90 90 90 3.63
0.000
0.000 0.000 0.000 0.000 0.000
Parallel
(D 2h )
90 90
0 3.70
0.000
0.000 0.000 0.000 0.000 0.000
Linear
(D ∞h )
0
0
0 5.22
0.000
0.000 0.000 0.000 0.000 0.000
Author’s calculations for r 1 = r 2 = 2.07 a 0 :
a HF method with aug-cc-pVTZ basis set plus midbond
functions (BSSE corrected);
b
MP2 method with aug-cc-pVTZ basis set plus midbond functions
(BSSE corrected);
c MP2 method with aug-cc-pVQZ basis set plus midbond functions (BSSE
corrected);
d
CCSD(T) method with aug-cc-pVTZ basis set plus midbond functions (BSSE
corrected);
e Modified model
Fig. 3.4 Components of the dipole moment (ea 0 ) of N 2 –N 2 complex calculated in the framework
of the modified induction model (the angles are in rad). R = 7.14 a 0 , r 1 = r 2 = 2.07 a 0 , φ = π/2
3.2 Dipole Moment of van der Waals Complexes
27