Transport coefficients of classical dense fluids: a simple approach

Abstract

We have used theoretical values of the sum rules in the information theory for the transport coefficients from work of Heyes and Powles, and have found that there is no noticeable improvement in the results for the diffusion coefficient of a Lennard-Jones fluid over their results obtained using an indirect method for the evaluation of the sum rules. We also propose a phenomenological form involving two parameters for the time development of the time correlation function. The parameters are determined from the frequency sum rules of the respective time correlation function to incorporate exactly its short-time behaviour. The values of the sum rules and Green-Kubo expressions are used to determine self-diffusion, shear viscosity and thermal conductivity of Lennard-Jones fluids over wide ranges of density and temperature. A reasonable agreement with computer simulation data is obtained for all the transport coefficients.