Far infrared absorption of diatomic polar molecules in simple liquids and statistical properties of the interactions. I. Spectral theory

Abstract

A theory of the far infrared spectra of diatomic polar molecules dissolved in simple liquids is presented. The starting point is a basic spectrum of additive Lorentzian lines, whose widths and shifts are expressed up to second order with respect to the interaction. This basic spectrum is distorted by the finite correlation time of the interaction, by the correlation between initial states, and by the overlap between the lines which are not completely resolved for the liquid state. All these deviations, including the overlap correction, which leads to a nonadditivity effect of the lines, are also treated up to second order with respect to the interaction.