Ab initio study of intermolecular potential for dimers XO–HE (X=N,C)

The supermolecular MPPT approximation is applied to the study of the interaction energy of CO–He and NO–He dimers. The 6–311+G basis set with the addition of Sadlej’ polarization functions is shown to be appropriate for describing the spatial structure of the intermolecular potential. The necessity of the CP procedure is confirmed, and it is used to obtain correct values of the interaction energy at the MP4 level of theory. For both dimers, only one minimum of the potential surface is found in the case of the collinear spatial configuration: −0.419 kcal/mol for CO–He and −0.491 kcal/mol for NO–He. The influence of the one electron open shell at the NO–He dimer in comparison with the CO–He is estimated to be associated with a 15% increase in the interaction energy in the medium distance region.