Theoretical Characterization of the Trends in Halogen Bonding - Halogen Bonding: Fundamentals and Applications - page 5

The most important calculated and experimental monomer data, such as
equilibrium distances, dipole moments, polarizabilities, and the harmonic vi-
brational frequencies of the dihalogens XY, are reported in Tables 1-4.
Overall, the trends in the calculated XY properties are satisfactorily re-
produced with all four approaches: MP2, CCSD(T), B3LYP, and BH&HLYP.
For the harmonic vibrational frequencies, the CCSD(T) data are far superior.

Table 1 Calculated equilibrium bond distances [A] of the dihalogens as obtained with
different methods applying the aug-cc-pVTZ basis set [35]

MP2 CCSD(T) B3LYP BH&HLYP Exp. Refs.

F 2 1.401 1.418 1.397 1.361 1.412 [26]

ClF 1.638 1.647 1.649 1.615 1.628 [26]

Cl 2 1.999 2.020 2.024 1.996 1.988 [26]

BrF 1.758 1.765 1.775 1.742 1.759

BrCl 2.138 2.160 2.170 2.141 2.136

Br 2 2.279 2.303 2.317 2.286 2.281

Table 2 Calculated dipole moments [D] of the dihalogens ClF, BrF, BrCl, and NH 3 as
obtained with different methods applying the aug-cc-pVTZ basis set [36]

MP2 B3LYP BH&HLYP Exp. Refs.

ClF 1.64 1.65 1.62 1.63 [36]

BrF 1.32 1.39 1.41 1.29 [36]

BrCl 0.45 0.49 0.48 0.57 [36]

NH 3 1.52 1.49 1.51 1.47 [36]

Table 3 MP2/aug-cc-pVTZ calculated polarizabilities ( α , α zz , α xx ) [a.u.] of the dihalogens

F 2 ,ClF,Cl 2 , BrF, BrCl, and Br 2

Exp. or calc. a

MP2 Refs.

9.31 b

F 2 7.83, 11.21, 6.14 [37]

22.48 c ClF 17.94, 22.39, 15.71 [38]

30.98 b

Cl 2 30.33, 41.55, 24.72 [37]

27.82 c BrF 23.61, 28.08, 21.38 [38]

51.50 c BrCl 36.98, 50.54, 30.20 [38]

47.37 b Br 2 44.08, 60.83, 35.70 [37]

a

Experiment or superior calculation

b

α

from experiment

c

α zz calculated (MBPT(4))