Models of the orientational autocorrelation function from far infrared absorption in liquid and rotator phases

Abstract

Orientational time-autocorrelation functions derived from (i) a multi-site model, (ii) an itinerant oscillator model, and (iii) the J-diffusion model, of molecular motion in liquid and rotator phases are compared and contrasted in the 1 to 4 ps interval for symmetric top molecules. In contrast to the corresponding spectral bandshapes, these correlation functions are easily distinguishable, and yield information about the structuring of each phase.