Dynamical correlations in binary liquids. IV. Fourth moment of current and its application

Abstract

For pt.III see ibid., vol.11, p.1269 (1978). The expressions for the fourth frequency moments of longitudinal and transverse current correlation functions are derived for binary liquids. The numerical calculations are done for a model of molten sodium chloride using the molecular dynamics data of Hansen and McDonald. The results are used to estimate the relaxation times corresponding to number and charge current fluctuations and are in reasonably good agreement (up to q<2.5) with those of Hansen and McDonald (1975). At large wavevectors the agreement is only qualitative.