Prediction of Self-Diffusion Coefficients of Fluids Based on Friction and Free Volume Theories

With a combination of friction and free volume theories, a new equation for calculating the self-diffusion coefficient is presented based on molecular dynamics simulation data in the literature. The equation could be applied to calculate the self-diffusion coefficient of real fluids in the gas or liquid phase. The equation was used to calculate the self-diffusion coefficients of 18 substances. The absolute average relative deviation was 13.79 %.