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Abstract: In this Letter the interaction of Li atoms with terrace sites of MgO(0 0 1) surfaces is characterized by combining EPR spectroscopy with theoretical calculations. The Li atoms adsorbed to MgO terrace sites show a reduction of the isotropic hyperfine coupling constant by approximately 50% with respect to Li atoms in the gas phase. In combination with theoretical calculations it can be shown that this reduction of the hyperfine coupling constant is not due to a charge transfer between Li and MgO but can be understood by a polarization of the Li atoms which are essentially neutral. [Copyright &y& Elsevier]

Abstract: N-doped titanium dioxide has been prepared generating a nitrogen plasma in the atmosphere over a sample of pre-reduced TiO2. This solid, investigated by EPR and XPS, is similar to materials prepared via sol–gel or different chemical methods. The cleaner preparation method, however, avoids complications in the assignments due to by-products of the chemical synthesis. The experiment unambiguously confirms previous theoretical forecast and indicates the formation of an interstitial paramagnetic nitrogen species already described in the case of sol–gel prepared materials. The energy of this species lies slightly over the valence band limit and well below the Ti3+ states of reduced TiO2. [Copyright &y& Elsevier]