Theoretical interpretation of the resonance Raman spectrum of gaseous chlorine

Abstract

A theoretical calculation of the Raman band profiles of gaseous chlorine excited by a 3638 Å line is performed. The resonance part of the Raman amplitude is calculated within a semiclassical approach and the nonresonant part by an ab initio calculation. The profiles of the overtones are well described by considering only the resonant scattering via the excited electronic state C 1Π(1u) and the anomalous value of the fundamental band intensity compared to the first overtone is shown to be due to virtual transitions to higher electronic states (normal Raman effect).