New results in the theory of collective self-diffusion in liquids

Abstract

Results of new researches concerning the collective nature of transfer phenomena in liquids are reported. Attention is concentrated on the consistent analysis of a nontrivial time dependence of the root-mean-square displacement (RMSD) of molecules. The account of the contribution associated with the collective component of the molecular motion is shown to result in a more adequate description of the RMSD of molecules at short time intervals. A new method for the determination of the Maxwell relaxation time, which is one of the most important dynamic parameters of molecular systems, is expounded. Mechanisms of one-particle diffusion in water and argon are proposed. The correlation between the results obtained and the results of molecular dynamics studies in computer experiments by G.G. Malenkov, Yu.I. Naberukhin, and V.P.Voloshin aimed at determining the dimensions of Lagrange particles are discussed. A brief historical review of the problem of self-diffusion in liquids is made.