Excess entropy scaling for transport coefficients: diffusion and viscosity in liquid metals

A semi-empirical universal relationship proposed by Rosenfeld for dimensionless transport coefficients in dense fluids, and a universal scaling law proposed by Dzugutov for atomic diffusion in liquids, are tested for diverse liquid metals using molecular dynamics simulations. Interatomic potentials derived from the glue potential and second-moment approximation of tight-binding scheme are used to study liquid metals; the angular dependent Tersoff potential and Stillinger-Weber potential are used to investigate Si. Our simulation results give sound support to the above-mentioned universal scaling laws. Following Dzugutov, we have also arrived at a universal scaling relationship between the viscosity coefficient and excess entropy. The simulation results suggest that there approximately exists an exponent correlation between the reduced transport coefficients and the corresponding packing density.