Molecular dynamic study of the melting temperature in MgF 2 with the fluorite structure

Abstract

The melting temperature of MgF 2 with cubic fluorite structure has been calculated by the constant temperature and pressure molecular dynamics (MD) simulation using the well-tested effective pair-wise potentials, which consist of the Coulomb, dispersion, and repulsion interaction by varying temperature from 300 to 2500 K. It is found that the potential parameters for MgF 2 derived from ab initio periodic Hartree-Fock calculations are very successful in reproducing accurately the DFT-GGA combined with quasi-harmonic Debye model calculated volumes of the cubic fluorite-type MgF 2 over a wide range of temperature at room pressure. Our simulated melting temperature of cubic fluorite-type MgF 2 is very close to the actual melting temperature 1539 K. Meanwhile, the radial distribution functions of Mg–Mg, F–F, and Mg–F ion pairs near the melting temperature are investigated from the isobaric and isothermal ensemble.