Ab initio study of the optical transitions of F centers at low-coordinated sites of the MgO surface

摘要: Abstract We report ab initio calculations on the optical transitions of oxygen vacancies (F centers) located at low-coordinated sites MgO (100) surface. F and + centers terrace, step corner were investigated by means cluster models embedded in point charges. The transition energies to lowest excited states determined performing extensive configuration interaction where correlation effects are explicitly taken into account. due surface considerably red-shifted, ∼2.5 eV, compared bulk excitations. also found a decrease ∼0.5–1.2 eV those terrace sites. This trend is explained terms reduced Pauli repulsion state. According these results, should give rise two distinct bands. tentatively suggest that features 2.05 2.3 eV observed experimentally not terraces.