Theoretical study of the ν3 and ν4 Raman bands of methane in rare gas matrices

Abstract

Theoretical study has been carried out on the Raman spectra of the ν3 and ν4 vibration bands of methane in Ar, Kr, and Xe matrices at low temperatures. The present study is a continuation of a theoretical work by Nishiyama and Yamamoto on the infrared spectra of the same Systems. We consider the symmetry of the System under the group [Formula: see text] introducing the inversion functions to generalize Wigner's rotational functions. As a result, dual assignments are given to each vibration–rotation state. The allowed transitions of the Raman scattering are compared with those of the infrared absorption, and it is found that a kind of 'rule of mutual exclusion' holds. The relative intensities and spacings of the Raman spectra are calculated and successfully compared with experiment.