Mode-Coupling Analyses of Atomic Dynamics for Liquid Ge, Sn and Na

Abstract

The atomic dynamics of liquid Ge, Sn and Na are studied based on the mode-coupling theory. The memory functions for the velocity autocorrelation functions (VAF) are obtained for liquid Ge, Sn and Na numerically from the VAF obtained by the molecular-dynamics simulations and are divided into the binary-collision term and the mode-coupling term. For the liquid Na the memory functions are also calculated theoretically by the mode-coupling theory and compared with that obtained numerically. The characteristic features of the memory functions for the liquid Ge and Sn near the triple point are qualitatively different from those for the typical liquids and are similar to those of the memory function of the liquid Na at high temperatures, which cannot be described by the mode-coupling theory.