Interatomic Potentials; A Systematic Comparison between Experimentally Deduced and ab Initio Calculated for Twenty Liquid Metals

The effective potential energy of a system of ions in a metal is considered as the sum of a volume (position-independent) and a pairwis term. Qualitative allowance is made for the effect on the observed structure factor of the volume part and a redefined structure factor for pair interactions only is inferred. The direct correlation function of the latter then provides qualitative insight into the pair term. This procedure is used to analyse Waseda’s data for 20 liquid metals. Despite some considerable uncertainties, there is a clear correlation with a set of systematically calculated ab initio pair potentials which were obtained using Ashcroft pseudopotentials and Ichimaru-Utsumi screening.