Equation of State for Earth’s Mineral and MgSiO3-MgO System under High Compressions

Abstract The thermodynamic parameters of MgSiO3-MgO system have been calculated by employing the modified Shanker equation of state (EOS) named “Higher Order Shanker (HOS) EOS ”. The modification is based on the inclusion of higher order terms in Shanker EOS. The Higher Order Shanker (HOS) EOS has been assessed for consistency with Stacey criteria for the variation of the pressure dependence of isothermal bulk modulus. The comparative analysis of the thermodynamic properties obtained from Higher Order Shanker (HOS) EOS with existing classical EOS such as the Birch-Murnagham, the Shanker, the Vinet, the Stacey, and electronic contribution analysis demonstrate that the proposed Higher Order Shanker (HOS) EOS is reliable EOS for computing thermodynamic properties of similar systems at higher pressures. Expressions for the bulk modulus and its pressure derivatives have been derived and reduced to the limit of infinite pressure. The expression thus obtained are useful for further analysis of higher derivatives thermoelastic properties.