J. Phys. IV France 10 (2000) Pr7-41-Pr7-45
Size dependence of self-diffusion in dense binary liquid of hard spheresH. Kawai1, K. Froböse2, F. Kolbe2 and J. Jäckle2
1 Department of Physics, Kyushu University, Fukuoka, Japan
2 Department of Physics, University of Konstanz, Konstanz, Germany
For a very dense binary liquid of hard spheres the dependence of the velocity-autocorrelation function (VAF) of tagged particles and of the self-diffusion coefficient on system size is derived from the coupling of self diffusion to modes of collective flow. Collective flow is described by longitudinal and transverse current-current correlation functions for different wavevectors which are obtained by molecular dynamics simulation. The size dependence of the VAF is reproduced rather accurately for longer times t > 7τ, where τ is the mean time of free flight. The result for the size dependence of the self-diffusion coefficient is in satisfactory agreement with a direct calculation, but this result also depends on the VAF's at shorter times.
© EDP Sciences 2000