A quasiharmonic model calculation for two non-Markovian far-infrared spectra of diatomic polar molecules in a rare-gas liquid. II. Correlation functions of the interaction and spectral application to a HCl–Ar solution

In paper I, the theoretical TTOC and PTOC far-infrared absorption coefficients of diatomic polar molecules in rare-gas liquid have been expressed in terms of correlation functions of the Hamiltonian which describes the diatomic–medium interaction. In this paper these correlation functions are derived using a harmonic model for the liquid structure which takes into account some peculiarities such as dynamical behavior and geometrical arrangement of atoms in the liquid. The correlation functions and the different spectral contributions which appear in the spectral theory of paper I are numerically analyzed for a HCl–Ar solution. Comparison between theoretical and experimental spectra shows that the best agreement is obtained with the PTOC approach.