Theory of transport in liquid metals. I. Calculation of self-diffusion coefficients

An approach is presented for the theoretical calculation of self-diffusion coefficients of liquid metals. The basic assumption is that the self-diffusion coefficient of a liquid metal is equal to that of an appropriate hard sphere fluid. The hard sphere diameter is dependent upon temperature, and a method is developed for estimating this temperature dependence by exploring the relationship between the diameter and the interatomic potential energy function of the liquid metal. The theory gives accurate results for the magnitude and temperature dependence of the self-diffusion coefficient for many liquid metals. In addition, the physical basis for the theory is consistent with what has been learned about the liquid state from molecular dynamics calculations.