Self diffusion and binary Maxwell-Stefan diffusion in simple fluids with the Green-Kubo method

TL;DR

This paper uses equilibrium molecular dynamics with the Green-Kubo method to accurately predict self and binary Maxwell-Stefan diffusion coefficients in simple fluids, validating the approach across various noble gases and methane.

Contribution

It introduces a reliable Green-Kubo based simulation method for diffusion coefficients in simple fluids modeled by Lennard-Jones potentials, validated against experimental data.

Findings

Self diffusion coefficients predicted within 5-10% accuracy.

Maxwell-Stefan diffusion coefficients predicted within 10%.

Darken's model shows good agreement with simulation results.

Abstract

Self diffusion coefficients and binary Maxwell-Stefan diffusion coefficients were determined by equilibrium molecular dynamics simulations with the Green-Kubo method. The study covers five pure fluids: neon, argon, krypton, xenon, and methane and three binary mixtures: argon+krypton, argon+xenon, and krypton+xenon. The fluids are modeled by spherical Lennard-Jones air-potentials, with parameters which were determined solely on the basis of vapor-liquid equilibria data. The predictions of the self diffusion coefficients agree within 5% for gas state points and about 10% for liquid state points. The Maxwell-Stefan diffusion coefficients are predicted within 10%. A test of Darken's model shows good agreement.