A. Garcia et al., DENSITY-FUNCTIONAL STUDIES OF THE B-PI.A-SIGMA CHARGE-TRANSFER COMPLEX FORMED BETWEEN ETHYNE AND CHLORINE MONOFLUORIDE, The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 101(16), 1997, pp. 3021-3024
The b pi.a sigma charge-transfer complex formed by ethyne and chlorine
monofluoride has been studied with various approximate pure and hybri
d density functional methods and the second-order Moller-Plesset (MP2)
theory. The calculations demonstrate that one hybrid method, namely,
the so-called B3LYP, leads to reasonably good estimates of the experim
entally measured rotational constants. Accordingly, the predicted B3LY
P intermolecular distance is found to be also close to the experimenta
l value. This enables us to estimate reliably the intermolecular inter
action energy, which is found to be 3.43 kcal/mol. The performance of
the various approximate density functionals and the MP2 theory is comp
ared and discussed. Finally, we comment on the analysis of the natural
bond orbitals, which has been found to be very valuable to shed light
on the nature of the weak intermolecular interaction.