Abstract
Using ab initio total energy based on density functional theory calculations, the phase transition, band structure, optical spectra and magnetic moment of MnO in the rock salt structure have been investigated. All studied quantities are discussed with respect to their dependence on pressure. Our results show a phase transition of MnO from the semiconducting rock salt to a metallic CsCl at pressure of 67.12 GPa. Applied pressure is found to play an important role in the modulation of optical properties. The optical absorption coefficient indicates that MnO more readily absorb photons under high pressure. The total magnetic moment for rock salt MnO at zero pressure agrees reasonably well with those reported in the literature and decreases monotonously with increasing pressure.