Infrared, Raman and microwave studies of the molecular dynamics and interactions in liquid benzonitrile

Abstract

Studies on the ‘single particle’ (infrared) and collective (far-infrared and microwave) reorientational motions of benzonitrile liquid have shown that rotation is relatively slow. The static and dynamic total dipole correlations are sensibly described by the Glarum-Powles relationship between collective and single molecule times. These correlations include (at least) a contribution from short-ranged potentials. The total dipole density correlation function is successfully described by the Lynden-Bell/Steele gaussian cage model for libration in quasi-static cages but with parameters which predict intermolecular torques smaller than for more rapidly rotating liquid phase molecules. There is also some indication of a time scale separation between collective reorientational and interaction-induced dipole fluctuations.