Calculations are made for clusters simulating the Vk‐center in NaF and a hypothetic self‐trapped hole in MgO within the embedded cluster approach. The “non‐ionic” charge configuration of MgO, described earlier, is analysed as a possible cause of the absence of the hole self‐trapping manifestations in the oxide according to the mechanism known for NaF. Due to the delocalization of oxygen 2p‐states the hole orbital is oriented, in contrast to NaF, perpendicularly to the 2‐anion quasi‐molecule axis, while the hole state itself lies close to the top of the potential barrier bonding this state.

The electronic structure of CaO and SrO in the ground state is calculated in terms of the crystalline cluster approach. Calculations for 27‐atom clusters at different ratios between muffin‐tin sphere radii show that in both crystals the charge configuration is similar to that obtained earlier for MgO: Mg2+ ‐O− plus one electron, distributed in the interstitial region. Such distribution of the electronic density is interpreted in terms of the theory of resonance scattering on the anion effective potential.

No abstract

The recently developed crystalline cluster method within the framework of the Johnson multiple scattering technique was successfully used in calculations of ionic cubic crystals and the defects with a cubic symmetry. In this paper a simple way of extension of the method to noncubic systems by a partial elimination of "muffin-tin" approximation (MTA) is proposed.The procedure suggested does reduce the intermediate integrals to the one-dimensional ones, and they are calculated analytically. It is supposed that an approach of taking into account the nonspherical shape of the potential inside the "muffin-tin" (MT) spheres will be effective in crystals with an ionic type of chemical bond.

No abstract