Diffusion in binary mixtures: an analysis of the dependence on the thermodynamic factor

Abstract

We study the diffusion process in binary mixtures using transition probabilities that depend on a mean-field potential. This approach reproduces the Darken equation, a relationship between the intrinsic and the tracer diffusion coefficients, $D_A$ and $D_A^{\ast }$, through the thermodynamic factor $\Phi$ (a function of the derivative of the activity coefficient against molar fraction). The mean-field approach allows us to go beyond the Darken equation and separately specify the dependence of $D_A$ and $D_A^{\ast }$ on the thermodynamic factor. We obtain that $\Phi$ appears in the expression for $D_A^{\ast }$, but the intrinsic diffusivity $D_A$ turns out to be independent of $\Phi$. Experimental results taken from the literature on diffusion in metal alloys are consistent with this theoretical prediction.

7pages, 2 figures

References in corpus (1)

• From diffusion experiments to mean-field theory simulations and back

Cited by in corpus (4)

• Application of the Widom insertion formula to transition rates in a lattice
• Out-of-equilibrium Monte Carlo simulations of a classical gas with Bose-Einstein statistics
• The role of the thermodynamic factor on the intrinsic and tracer diffusivities in binary mixtures
• Transition state theory applied to self-diffusion of hard spheres