SELF-VELOCITY AND CROSS-VELOCITY CORRELATION-FUNCTIONS AND DIFFUSION-COEFFICIENTS IN LIQUIDS - A MOLECULAR-DYNAMICS STUDY OF BINARY-MIXTURES OF SOFT SPHERES

Molecular dynamics simulation is applied to the study of the diffusion properties in binary liquid mixtures made up of soft-sphere particles with different sizes and masses. Self- and distinct velocity correlat ion functions and related diffusion coefficients have been calculated. Special attention has been paid to the dynamic cross correlations whi ch have been computed through recently introduced relative mean molecu lar velocity correlation functions which are independent on the refere nce frame. The differences between the distinct velocity correlations and diffusion coefficients in different reference frames (mass-fixed, number-fixed, and solvent-fixed) are discussed.