Theoretical Study of the Effect of High Pressure on the Elastic and the Thermal Properties of MgO

Elastic-Thermo properties of alkaline earth oxide MgO have been studied by using two types of Equation of State ( EOS ), Isothermal Shanker EOS and Modified Kumar EOS. The elastic moduli, sound velocities and the pressure-compression relationship of MgO have been studied up to a pressure 150 GPa by using Shanker EOS which depends on volume short-range force constant of inter atomic potentials. The results show agreement with the researcher results Upadhyay and Sharma. The relationship between the solid density and elastic moduli gave values both of compression and shear waves velocities, the theoretical results are below rate about 6% with the whole range of the experimental data. The thermal properties at high( temperature and pressure) of MgO have been studied by applying unified theory of Kumar EOS, this theory based on thermodynamic analysis and to the thermal expansion,thus the inharmonic term is arising and used in the calculation of thermal properties of MgO. The results which are obtained from the effect of high temperature and high pressure on MgO properties are fitting with an experimental data. Keywords: MgO, elastic moduli, thermal properties under high pressure, equation of state (EOS).