Dynamical Correlation Functions and Memory Functions of Liquid Sodium -- a Molecular Dynamics Simulation

The dynamical properties of liquid sodium at 380 K near the triple point are studied by means of a constant-temperature molecular dynamics simulation. For the interaction between ions, the effective pair potential based on the pseudopotential theory is adopted. The dynamical correlation functions are calculated for several wave vectors and the associated memory functions are obtained by solving the causality equation. The profiles of the memory functions are discussed in detail and some characteristic features are clarified. It is shown that the transport coefficients such as the diffusion constant D and the shear viscosity eta are in agreement with those determined experimentally.