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arXiv · 1707.00423

Generalized Einstein relation for the mutual diffusion coefficient of a binary fluid mixture

B. U. Felderhof
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Abstract

The method employed by Einstein to derive his famous relation between the diffusion coefficient and the friction coefficient of a Brownian particle is used to derive a generalized Einstein relation for the mutual diffusion coefficient of a binary fluid mixture. The expression is compared with the one derived by de Groot and Mazur from irreversible thermodynamics, and later by Batchelor for a Brownian suspension. A different result was derived by several other workers in irreversible thermodynamics. For a nearly incompressible solution the generalized Einstein relation agrees with the expression derived by de Groot and Mazur. The two expressions also agree to first order in solute density. For a Brownian suspension the result derived from the generalized Smoluchowski equation agrees with both expressions.

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B. U. Felderhof. 2017-07-03. Generalized Einstein relation for the mutual diffusion coefficient of a binary fluid mixture. https://doi.org/10.1063/1.4993958

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