O- radical ions on MgO:: a tool for a structural description of the surface

The present contribution aims to show that detailed information on structure and location of surface defective sites (surface vacancies, low co-ordination sites) can be obtained by combining data on the chemical reactivity of polycrystalline surfaces and EPR data. The use of nitrous oxide for bleaching trapped electron centres at the surface of MgO produces a remarkable variety of O- species, which differ in their values of the energy splitting (deltaE) term between the p, and the other two p orbitals of the radical ion. This indicates the existence of a corresponding variety of surface traps having different structural features.