Microscopic Transport Phenomena in a Liquid Alkali Metal K39

Abstract

Microscopic equations of an interacting and correlated system of particles has been solved to compute two of the transport properties, namely diffusion coefficient and longitudinal viscosity, of liquid potassium near its melting point, at 343K, for a wave vector range: 0.9 nm −1 to 17.0 nm −1 . The present theoretical approach uses microscopic theory as a tool to compute the detailed dynamical structure factor, current-current correlation function and hence, the diffusion coefficient as well as the coefficient of longitudinal viscosity. Microscopic theory uses interparticle-interaction present among particles of a liquid to yield density-density response function and hence, its complete dynamics. The diffusion coefficient is evolved as a realistic parameter which has been fit to explain the experimental dynamical structure factors. The coefficient of longitudinal viscosity on the other hand is directly related to static structure factor and diffusion coefficient in the regime where wavevector and frequency approaches zero. It also depends upon velocity of sound which, in the present communication, has been calculated from peak positions of current-current correlation functions in the limit wavevector approaches zero. Computed results for both of the transport coefficients, self diffusion coefficient and longitudinal viscosity are found to agree well with the corresponding experimentally reported values.