Analysis of compressibility and thermal expansivity for MgSiO3 perovskite

An analysis of the compressibility of MgSiO3 perovskite under high pressure and at room temperature has been presented. The pressure-volume isothermal relationship, isothermal hulk modulus and its pressure derivative have bee n calculated at high pressures, down to a compression of fifty percent, usi ng the Birch-Murnaghan third order equation of state (EOS) [J Geophys Res 5 7(1952) 227], the Vinet EOS [Phys Rev 8, 35 (1987) 1945] and the Shanker EO S [Physica B, 239 (1997) 337].The results obtained from the Vinet universal EOS have been used further to investigate the volume thermal expansion at high pressures along isobars for the silicate perovskite under study with t he help of the Shanker equation of thermal expansivity. The calculated valu es of volume thermal expansion have been found to present good agreement wi th the recent experimental data.