Microscopic theory of collective anisotropic molecular reorientation

Abstract

Mori's method is applied to the calculation of the collective molecular orientation correlation functions which are of interest in light scattering and dielectric relaxation. The case of liquids composed of asymmetric top molecules is discussed. For the collective variables, the usual ‘rotational diffusion’ assumptions do not yield the single-particle rotational diffusion results unless there exists no orientational order in the medium. This point is discussed with regard to the results of some recent light scattering and dielectric relaxation experiments.