Coordination behavior of the core and valence levels of low-coordinated oxygen ions on the surface of magnesium oxide

For low-coordinated (N=2,3,4,5) oxygen ions on the surface and in the bulk of magnesium oxide, the behavior of the core O1s- and valence O2s-, O2p-levels is considered. The MgO ₆ ¹⁰⁻ , OMg ₆ ¹⁰⁺ , Mg₁₃O ₁₄ ²⁻ , O₁₃Mg ₁₄ ²⁺ , Mg₄O ₇ ⁶⁻ , and OMg ₂ ²⁺ clusters are calculated by the SCF-Xα-SW method. The binding energies of oxygen 1s-, 2s-, and 2p-states decrease with coordination. This coordination dependence is explained by the greater change of the Madelung potential as compared to variations of the purely electronic terms of the binding energies of oxygen ions. The dependence of oxygen atomic charges and relaxation energies on coordination is also discussed. Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 1, pp. 16–26, January–February, 1995. Translated by the authors