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Concentration and mass dependence of transport coefficients and correlation functions in binary mixtures with high mass-asymmetry

Correlation functions and transport coefficients of self-diffusion and shear viscosity of a binary Lennard-Jones mixture with components differing only in their particle mass are studied up to high values of the mass ratio $μ$, including the limiting case $μ=\infty$, for different mole fractions $x$. Within a large range of $x$ and $μ$ the product of the diffusion coefficient of the heavy species $D_{2}$ and the total shear viscosity of the mixture $η_{m}$ is found to remain constant, obeying a generalized Stokes-Einstein relation. At high liquid density, large mass ratios lead to a pronounced cage effect that is observable in the mean square displacement, the velocity autocorrelation function and the van Hove correlation function.