Thermodynamic properties of MgO under high pressure from first-principles calculations

The equations of state (EOS) and other thermodynamic properties of the rocksalt (RS) structure MgO are investigated by ab initio plane-wave pseudopotential density functional theory method. The obtained results are consistent with the experimental data and those calculated by others. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the dependences of relative volume V/V-0 on pressure P, cell volume V on temperature T, and Debye temperature Theta and specific heat C-V on pressure P are successfully obtained. The variation of the thermal expansion alpha with temperature and pressure is investigated, which shows the temperature has hardly any effect on the thermal expansion alpha at higher pressure. (c) 2005 Elsevier B.V. All rights reserved.