  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 $\mu$,
including the limiting case $\mu=\infty$, for different mole fractions $x$.
Within a large range of $x$ and $\mu$ the product of the diffusion coefficient
of the heavy species $D_{2}$ and the total shear viscosity of the mixture
$\eta_{m}$ 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.
