Inhomogeneous broadening of vibrational linewidths in polyatomic liquids

Publisher Website
Google Scholar
Abstract
The first account of inhomogeneous broadening of vibrational linewidths in non‐hydrogen‐bonded liquids is presented based on the combined results of isotropic spontaneous Raman studies and picosecond coherent probing experiments. The symmetric CH3‐stretching vibrational linewidths studied were found to be inhomogeneously broadened to various degrees. A correlation between the inhomogeneous broadening and the liquid’s local number density distribution width is demonstrated, upon which a theoretical model for inhomogeneous broadening is developed. A stochastic line shape theory is constructed in which homogeneous and inhomogeneous broadening are treated simultaneously in terms of one vibrational correlation function. This treatment unifies the fast and slow modulation approaches to vibrational dephasing and demonstrates how isotropic spontaneous Raman scattering studies and picosecond coherent probing experiments can be used in conjunction to study the inhomogeneous broadening of vibrational linewidths.