Hydrodynamics of acoustic phonon-molecular reorientation coupling in plastic crystals; vh scattering

Abstract

A model is developed to describe the coupling between the reorientation of anisotropic molecules and acoustic modes in a plastic crystal. The model is applied to the calculation of depolarized VH light-scattering spectra of cubic plastic crystals. It predicts two distinct overdamped reorientation-like modes and the appearance of shear phonon-like modes with resonance line-shapes, in agreement with experimental observation