Excess Entropy, Diffusion Coefficient, Viscosity Coefficient and Surface Tension of Liquid Simple Metals from Diffraction Data

Abstract

In this paper we will provide a prescription for evaluating properties of liquid metals from measured diffraction data. When a liquid metal structure factor is of hard-sphere form, there is a correlation between structure factor and entropy. This is investigated for liquid alkali, noble and typical polyvalent metals. First of all, we calculate the pair and triplet correlation entropies (S(2) and S(3)) from the measured diffraction data. To evaluate the triplet correlation entropy S(3), we do not use the superposition approximation of Kirkwood. Next, assuming that the excess entropy (i.e., ion configurational entropy) SE is given as S(2)+S(3)+S(x), where S(x) denotes an entropy contribution arising from the four-body and higher-order terms of correlations, we calculate the self-diffusion coefficient D based on Dzugutov’s scaling law. By means of D, we estimate the viscosity coefficient η and the surface tension γ for these liquid metals using the Stokes-Einstein relation, the Born-Green equation and Fowler’s formula for the surface tension. We can find there exists a clear relationship between SE, D, η and γ. Predicted values of D, η and γ are reasonable in size in comparison with the available experimental data.