Abstract
Dynamical cross-correlation functions are reported for the diffusion of spherical-top molecules, exemplified by the Td-symmetry molecule carbon tetrachloride in the liquid state at 296 K. These are novel types of cross-correlation functions which exist directly in the laboratory frame of reference, (x,y,z), and involve rotational and translational motion simultaneously. Contemporary analytical theories for the diffusion of the spherical top are not able to account for these results, which were obtained by computer simulation.