Evaluation of the multipole-induced-multipole model: incremental dipole polarizabilities in the CH₄…He system

Abstract

The validity of the multipole-induced-multipole (MIM) model as applied to the intensity of collision induced rotational Raman scattering is examined in terms of directly calculated incremental dipole polarizabilities for the CH₄…He system. The results of HFSCF and MBPT calculations are compared with the MIM data determined by using the dipole and dipole-quadrupole polarizabilities computed in this study at the level of the fourth order MBPT approximation. It is concluded that the long range interaction model may be sufficient for the determination of molecular dipole-quadrupole polarizabilities from the Raman scattering data. However, the determination of the next term in the MIM expansion will considerably suffer from the neglect of the valence repulsion contribution.