Rotational diffusion model with a variable collision distribution. II. The effect of energy transfer

In this paper we present the results of model calculations on the rotational motion of linear molecules in dense systems. To this end we have developed a matrix description for the rotational diffusion, which is extended in this article to the J-diffusion limit. Closed expressions are obtained for the orientational, angular momentum, and rotational energy autocorrelation functions. The precise time dependence of these correlation functions is determined by the time distribution of collisions and the magnitude of energy and momentum transfer during a collision. A systematic analysis of the role of these two effects on the rotational relaxation is presente