Elastic moduli of solid helium at megabar pressures

Abstract

Elastic moduli and equation of state of highly compressed solid He are calculated up to the pressure 1.5 Mbar. While calculating the energy of the crystal, pair interatomic interactions and three-body interactions are taken into account. Three-body contribution is significant to a great extent both for the equation ofstate and for the elastic moduli and makes considerable softening of the equation of state. On the other hand, vibrational characteristics, such as the sound velocity and the Debye temperature, do not strongly depend on the inclusion of non-additive interactions.