Shock-data constraints on interatomic potentials for condensed matter

It is customary to represent the shock Hugoniot as a linear relation betwee n shock velocity and the particle velocity behind the shock It has been rec ently shown that the coefficients appearing in the general expansion of sho ck velocity as a power series in particle velocity can be calculated, to ar bitrary order, from the derivatives of the shock pressure with respect to v olume, evaluated at the initial state. The first two coefficients in the ex pansion have a simple relation to the interatomic potential describing the material. Most such potentials contain just two parameters (roughly, a "str ength" parameter and a "shape" parameter), which can be conveniently extrac ted from the shock parameters. We present results for the values of the pot ential parameters, for several commonly-used forms of potential determined by least-squares fitting of the shock data to nonlinear Hugoniots. The resu lts obtained sometimes differ from those obtained on the assumption of a li near Hugoniot. (C) 1999 Elsevier Science Ltd. All rights reserved.