Ab initio molecular orbital studies of the vibrational spectra of some van der Waals complexes. Part 3: Complexes of carbon monoxide with carbon dioxide, nitrous oxide, carbonyl sulphide and carbon disulphide

The properties of the molecular electron donor-acceptor complexes formed between carbon monoxide, as the electron donor, and the linear triatomic molecules carbon dioxide, nitrous oxide, carbonyl sulphide and carbon disulphide as the electron acceptors, have been studied. These properties include their structures, interaction energies and vibrational spectra. The studies were performed using the Gaussian 98 computer program, at the second order level of Møller-Plesset perturbation theory (MP2) with the 6-311+G(d) basis set. The interaction energies are inversely dependent on the absolute electronegativities, mean polarizabilities and quadrupole moments of the electron acceptors, at least for CO2, OCS and CS2, while the CO stretching wavenumber shifts generally become more positive with increasing interaction energy. The results obtained will be useful in further studies of these complexes using the matrix isolation infrared spectroscopic technique.