BULK AND SURFACE ELECTRONIC-STRUCTURES OF MGO

The bulk electronic structure of MgO is calculated from first principl es including correlation effects within the GW approximation. The band gap, the position of the 2s O band, and the valence band width are in good agreement with experiment. From the quasiparticle band structure , optical transitions corresponding to the main optical absorption pea ks are identified. The energy-loss spectrum is also calculated and com pared with experiment. The surface electronic structure of MgO(100) is calculated self-consistently within the local-density approximation. It is found that states observed in a recent photoemission experiment outside the bulk allowed states are close to surface states.