Structure and forces in liquid metals and alloys

Abstract

The so-called force equation relating the pair function g(r), the three-body correlation function, and the assumed pair potential [Formula: see text] is first discussed from the standpoint of extracting force fields from diffraction measurements of the structure factor of liquid metals. Recent progress has been possible in this area by making use of the modified hypernetted-chain approximation, including the bridge function.A discussion is then given that relates the bridge function to vacancy-formation energy in hot close-packed metals, and also to the structure factor of the liquid. The possible role of cooperative effects in liquid metals on the inversion procedure is considered, as is the relation between three-body direct and total correlation functions.Pressing further the relation between liquid structure just above the melting point and the hot solid, advances in the theory of freezing are considered. The so-called Verlet rule on the height of the principal peak of the structure factor at melting is considered in relation to Lindemann's Law.After a brief discussion of the relation between structure and forces in liquid-metal alloys, the theory of inhomogeneous systems used to discuss freezing is applied to liquid surfaces, and in particular to surface segregation. The final topic treated is that of the critical constants of the fluid alkali metals, where it is argued that Coulomb forces are of decisive importance.