Analysis of isothermal equations of state for magnesium oxide at high temperatures
Singh Meenakshi, Bindu S Sharma
The pressure – volume relationships for magnesium oxide at 300, 500, 1000, 1500, and 2000 K have been studied by the use of the Birch – Murnaghan equation of state (EOS), the Vinet universal EOS, and the Grover, Getting, and Kennedy (GGK) EOS. The isothermal bulk modulus, KT, and its first pressure derivative, KT‘, have also been calculated as a function of compression (V/V0) for magnesium oxide at different temperatures. The results have been compared with the corresponding values obtained by Isaak et al using the ab initio method. The comparison reveals that the GGK EOS yields the best agreement with the ab initio values. At extremely high compressions the Birch – Murnaghan EOS becomes less satisfactory whereas the GGK EOS and the Vinet EOS yield sufficiently close agreement with each other.