The repulsive part of the effective interatomic potential for liquid metals

Abstract

Structure factors obtained by neutron and X-ray measurements on five liquid metals, Na, K, Pb, Ga, and Zn, have been analyzed to extract information about the repulsive part of the effective interionic potential. It is shown that the repulsive part of the pair potential between the ions in liquid metals can be obtained from that part of the structure factor curve lying beyond the first diffraction maximum. A general form for a repulsive potential is presented. It is found that within this form a wide range of potentials will produce structure factor curves which are in agreement with the experimental data at large k values. This analysis uses an extension of the blip-function method for the calculation of the structure factor of a fluid whose interatomic potential is purely repulsive and short ranged. Several properties of the potentials found for each liquid metal studied are consistent with corresponding physical properties of the solids. The large uncertainty in the repulsive potentials extracted from the large k portion of the structure factors make it seem unlikely that quantitative information about the attractive and long range parts of the potential can be extracted from the small k portion of the structure factor.