Quantum chemical calculation of the electronic structure and energy spectrum of the ionic cubic crystals with the defects

A model of molecular claster in the form of an extended elementary cell and semiempirical calculation scheme MNDO-PM/3 were applied to study electronic charge distribution and energy spectra in ionic cubic crystals (on the examples of MgO, MgS, CdO) with such types of defects as the vacancies of anion-cation pair (on the surface and in the bulk), additional ionic pair on the surface and substitution of surface metal atom. There were established the peculiarities of the states in the ideal crystals spectra caused by the valent orbitals of the defect or near-defect atoms.