Thermodynamic properties and self-diffusion coefficients of simple liquids

Abstract

Pair distribution functions and thermodynamic properties for a system of 108 particles interacting with a hard-sphere modified Lennard-Jones (12, 6) potential have been calculated by the Monte Carlo technique for a range of reduced liquid densities and two reduced temperatures. It is shown that the introduction of a hard core significantly modifies the Lennard-Jones parameters for the noble gases. The friction coefficients proposed in the transport theories of Rice and Allnatt and of Palyvos and Davis have been calculated using the exact pair distribution functions. In the normal liquid range, contributions to the frictional force on a particle arising from hard sphere collisions and quasi-Brownian motion are shown always to be comparable. This result is contrary to the conditions under which the principal assumption of Brownian theory is applicable.