Thermal stability and thermal expansion studies of cubic fluorite-type MgF2 up to 135 GPa

Abstract

The thermal expansion of MgF2 with a fluorite structure has been investigated at high pressures using plane-wave pseudopotential scheme within the local density approximation correction in the frame of density functional theory based on the analysis of thermal stability using classical molecular dynamics simulations up to 6500K. To investigate the thermodynamic properties like as the P–V–T equation of state and volumetric thermal expansion coefficient αV of cubic fluorite-type MgF2 at extended pressure and temperature ranges, we apply the quasi-harmonic Debye model in which the phononic effects are considered. The P–V relationship and αV dependence of the pressure up to 135GPa at different temperatures, and the V–T relationship and αV dependence of the temperature up to the melting temperature 1500K at different pressures have been obtained.