SINGLE-PARTICLE MOTION IN LIQUID-SODIUM - A MODE-COUPLING ANALYSIS

The velocity autocorrelation function obtained in a computer experimen t was interpreted in terms of a mode-coupling (MC) theory proposed by Sjogren and co-workers. The system chosen is liquid sodium at two diff erent temperatures, 403 and 1003 K. The MC terms of the velocity-autoc orrelation function were separated into density-density, density-curre nt and current-current contributions, For the 'binary' contribution a simple model is used; it is found that for the low temperature this fu nctional form (with one adjustable parameter) gives reliable and satis factory results, while for higher temperatures the model is no longer applicable. Hence, for a comprehensive application of MC theory, a bet ter understanding of the binary effects is required.