The simulation of transport processes using the method of molecular dynamics. Self-diffusion coefficient

Abstract

The possibility is investigated of using the method of molecular dynamics for calculating the self-diffusion coefficient of liquids and gases. The exactness of calculation of the autocorrelation function of the velocity of molecules and of the self-diffusion coefficient is systematically estimated. The characteristic errors of the method are analyzed. Correlations are constructed which enable one to reduce the effect made on the results by the finiteness of the number of particles, by the time of calculation, and by the number of measurements. The method of molecular dynamics is used to obtain the self-diffusion coefficients of moderately dense gases and study the plateau values of self-diffusion coefficients. The calculations involve from 125 to 64 000 molecules.