Raman band shapes of a three-level vibrational system for a bath represented by a two-state stochastic process

Abstract

The isotropic Raman spectrum of the molecule described by a three-level vibrational system has been simulated for a bath modeled as a two-state stochastic process. The influence of the energy relaxation as well as the dephasing on the spectrum is demonstrated for different modulation speeds of the bath. The cumulant expansion and the projection-operator formalism description of the isotropic spectrum have been studied. The results show that the projection-operator method provides an accurate description of these spectra for all modulation speeds whereas the cumulant expansion technique reproduces the spectra in the fast modulation limit only.