Nonlinear transport phenomena: Analysis in terms of density expansions

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Abstract:

A microscopic calculation of the long-time tail in the autocorrelation function corresponding to the mutual diffusion coefficient is presented. Mode-coupling methods in the framework of a generalized Langevin equation are used to obtain the results. The calculation yields an expression for the mutual diffusion coefficient in terms of two quantities; a bare mutual diffusion coefficient D* and a complicated nonlinear transport coefficient. Density expansions of these transport coefficients are carried out in order to elucidate their structure. In particular, we investigate, for dense gases, the conditions under which reduces to a factored form involving the kinematic viscosity and diffusion coefficient, and the relation between D* and the usual mutual diffusion coefficient. © 1973 The American Physical Society.