Self-motion in liquid sodium

The theory of Singwi and Sj\"olander for atomic motion in classical fluids is used to study the self-correlations in liquid sodium. The detailed numerical calculations have been done for the velocity-autocorrelation function and its frequency spectrum using two recently developed interatomic potentials. The results are compared with those obtained by Schiff and Rahman from molecular-dynamics experiments. The recent experimental results of Cocking for quasielastic scattering in liquid sodium at 388 °K are also analyzed using the results obtained from the above two model potentials.