Many-atom Repulsive Interactions in Solid Argon at High Pressure

Abstract

The many-atom character of interactions in fcc solid argon at high pressures is discussed. The cubic elastic constants and violation of the Cauchy relationship as a function of hydrostatic pressure, which have been measured recently by Shimizu et al., are shown to be very well reproduced by a full-potential and all-electron total energy scheme with a generalized gradient approximation for the exchange-correlation energy functional. It is shown that an essential many-atom feature can most simply be introduced through some appropriate embedding or environment-dependent functions brought into pair-wise interactions.