Extension of the energy-corrected sudden model to anisotropic Raman lines:Application to pure N-2 - art. no. 062702

The Energy-Corrected Sudden (ECS) model is a well-established dynamical mod el to calculate rovibrational isotropic Raman linewidth and also to describ e overlapping between lines through the off-diagonal elements of the relaxa tion matrix. The extension of this model to anisotropic Raman or infrared l ines has been previously performed through the expansion of the tetradic (f our indices) relaxation supermatrix elements in terms of dyadic (two indice s) mechanical cross sections. This model required new parameters in the dia gonal elements of the dyadic matrices that are the relaxation cross section s of rotational angular momentum and of its associated second-order tensor. In this paper, a new approach of the extension of the ECS model for anisot ropic Raman and infrared branches is proposed, and developed on a strong ph ysical basis. This new model only needs the original ECS parameters determi ned through a fit of the experimental isotropic Raman Q linewidths to gener ate anisotropic Raman and infrared linewidths as well as line mixing coeffi cients.