Three-body-exchange interaction in dense rare gases

Abstract

Self-consistent phonon calculations are employed to demonstrate the importance of the three-body-exchange interaction in dense rare-gas solids. A Slater-Kirkwood form is adopted, the parameters of which are adjusted on ab initio calculations for helium and argon and calculated by a scaling law for krypton and xenon. When used in conjunction with realistic (Aziz) pair potentials and the Axilrod-Teller terms, the exchange interaction brings the calculated equation of state for each rare gas into excellent accord with experiment. This type of interaction should stabilize the hcp structure for all rare gases below 90 GPa.