Structural and thermodynamic properties of MgSiO_3 perovskite under high pressure and high temperature

摘要

The structural and thermodynamic properties of MgSiO_3 perovskite is simulated using the constant temperature and pressure molecular dynamics simulations method combined with effective pair potentials consisting of Coulomb, dispersion, and repulsion interaction at high temperature and high pressure. It is shown that the simulated molar volume of MgSiO_3 perovskite is very successful in reproducing accurately the experimental data over a wide range of pressure and temperature. The simulated temperature dependence of the thermal expansion coefficient of MgSiO_3 perovskite is in agreement with the experimental data of Knittle and Jeanloz at zero pressure and other theoretical values at high pressure, respectively. The simulated thermal expansion coefficient and their pressure dependence favour the experimental data of Funamori et al. and Wang et al. at 500 K.