Theoretical studies of the collision-induced Raman spectrum of carbon dioxide

Abstract

Ab initio calculations have been performed on carbon dioxide to obtain the first derivatives of the dipole-quadrupole polarizability A and of the first hyperpolarizability β in the bending and asymmetric stretching modes. These derivatives are used to assess the relative contributions of A and β to the collision-induced Raman spectrum. It is concluded that most of the intensity arises from the mechanism involving the A tensor. Reasonable agreement is obtained with measured depolarization ratios and relative intensities for the v ₂ and v ₃ modes in compressed gaseous CO₂.