MODEL FOR SELF-DIFFUSION COEFFICIENT

In this study, we have relaxed one of the assumptions made in the mode l proposed by Tankeshwar, Singla and Pathak (1991, J. Phys.: Condens. Matrel 3, 3173). We have used a Debye spectrum of frequencies instead of a fixed frequency and have derived an analytical expression for the velocity auto-correlation function of the fluid. It is found that the use of the spectrum of frequencies rather than a single frequency doe s not improve the prediction of the model for the self-diffusion coeff icient as has been judged by comparing the results with molecular dyna mics data.