A molecular dynamics study of the hard dumb-bell system

Abstract

We have carried out a number of molecular dynamics simulations of the diatomic fused hard sphere or hard dumb-bell system. We have studied a selection of state points in the liquid phase, and also examined a plastic crystal and a normal crystal state. Our simulations provide details of time correlation functions for linear and angular velocities and orientational functions, which are compared with standard J-diffusion and truncated cumulant expansion approximations. We also examine the distribution of collision points on the molecular surface. At high density and high bond length, side-on collisions are favoured, while at low density and bond lengths the collisions are distributed more uniformly. Site-superposition approximations are moderately successful at reproducing these results for elongated molecules.