PNNL

Abstract

A semiclassical theory based upon the Robert-Bonamy formalism has been developed in order to explain the experimental measurements of self-broadening, self-induced pressure shift coefficients in the v1, v2, 2v2 bands of H12C14N and the 2v1 band of H13C14N as well as the temperature dependences of these parameters with special emphasis on the v2 band. Our calculations include only electrostatic interactions and neglect the vibrational dependence of the isotropic part of the intermolecular potential, which probably has a weak contribution to the HCN self-shifts for the bands investigated in this study. The agreement between theory and measurements is good in the cases of self-broadening coefficients and their variation with temperature, as well as the self-shift coefficients determined at room temperature. However, the observed temperature dependence of self-shift coefficients in the v2 band is different from that derived theoretically.