Collisional polarizability correlation functions: A step towards rotational-translational coupling

Abstract

A theory of the spectral distribution of the molecular time correlation function of the collision induced polarizabilities active in the collision induced light scattering has been developed. Within the framework of this approach a new concept of the averaging procedure is proposed, which - unlike the usually applied assumptions of total separation of the angle dependent and the translational contributions - partially includes the coupling between the rotational and translational degrees of freedom due to anisotropic intermolecular interactions. Introduction of the rotational spectral functions, valid for different frequency ranges, in order to produce a numerically treatable method of deriving collisional spectral profiles is discussed. The final results of the theory are formulated in a fashion providing a solid base for numerical calculations capable of interpreting data obtained in various fields of physical, environmental and astrophysical sciences.