We present a survey of recent theoretical studies of radiation-induced point defects in simple oxides with emphasis on highly ionic MgO, partly-covalent corundum (Al2O3) and ferroelectric KNbO3. The atomic and electronic structure of the electronic (F+ and F centers) and hole centers, as well as interstitial atoms therein are discussed in light of the available experimental data. Results for defect diffusion and photo-stimulated F+ → F center conversion are also analyzed.
Nuclear Instruments and Methods in Physics Research Section B, Volume 141, 1998, Pages 1-15

The atomic and electronic structure of H- ions substituting for O2- ions in regular sites in MgO crystals are calculated using an ab initio Hartree-Fock (HF) cluster approach and its semiempirical version, intermediate neglect of the differential overlap. The theoretical optical absorption energy is predicted to be 10 eV, which is supported by analysis of experimental data for the H- centers in a series of ionic crystals. The HF simulations of H- ion diffusion via direct interstitial hops along the [100] axis predict an activation energy of about 3 eV.
Phys. Rev. B 59, 1885 - 1890 (1999)

Semiempirical quantum chemical simulations have been undertaken to obtain the self-consistent atomic and electronic structure of the two basic electron defects in MgO crystals: F+ and F centres (one and two electrons trapped by an O vacancy, Va. The calculated absorption and luminescence energies agree well with the experimental data; the excited states of both defects are found to be essentially delocalised over nearest-neighbour cations. The activation energy for diffusion is found to increase monotonically in a series Va → F+ → F centre (2.50eV, 2.72 eV and 3.13 eV, respectively).
Materials Science and Engineering B Volume 37, Issues 1-3, February 1996, Pages 212-214

Semi-empirical quantum chemical simulations of 125-atom clusters have been undertaken to obtain the self-consistent atomic and electronic structure of the two basic electron defects in MgO crystals — F+ and F centers (one and two electrons trapped by an O vacancy). The calculated absorption and luminescence energies agree well with the experimental data, the excited states of both defects are found to be essentially delocalized over nearest-neighbour cations. The mechanism of the F+ → F photoconversion is discussed.
Computational Materials Science, Volume 5, 1996, Pages 298-306

Optical absorption measurements were used to monitor the thermal annihilation of oxygen vacancies (F-centers) in thermochemically reduced MgO crystals. The annihilation characteristics were sample-dependent and varied strongly with the F-center concentration. Different mechanisms for the destruction of F centers are suggested depending on their concentration.
Solid State Communications, Volume 118, 2001, pp.163-167