A model was presented for a new paramagnetic defect center which resulted from the interaction of atomic H with the MgO(100) surface. DFT calculations were performed by using periodic super-cells and embedded cluster models where long-range polarization effects were included explicitly. The H atom promotes the creation of an O vacancy (F center) by formation of the FS+(OH-) defect where an hydroxyl group was adsorbed near to an electron trapped in an O vacancy. This new center had some characteristics similar to those of the classical FS+ centers but a smaller formation energy. Being globally neutral, it could also be treated by using super-cell methods.

FS+ and FS+(OH-) Defect Centers at the MgO(100) Surface - Cluster and Periodic Calculations. M.Ménétrey, A.Markovits, C.Minot, A.Del Vitto, G.Pacchioni: Surface Science, 2004, 549[3], 294-304