The adsorption properties of water on the stoichiometric (101) surface of anatase TiO2 in the temperature range 160–400 K has been studied by synchrotron radiation core level photoelectron spectroscopy. O 1s spectra give clear evidence for the formation of a first layer of water that comprises both H2O and OH. The composition is 0.77 ± 0.05 ML H2O and 0.47 ± 0.05 ML OH. Decreasing the coverage by heating leads to a decreased H2O/OH ratio. The results are very similar to those recently reported for water on rutile TiO2(110) and show that the previously proposed model of molecular adsorption only on anatase TiO2(101) must be revised.

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Using photoionization, photoabsorption, and deexcitation spectroscopies the dynamics of the N I5 core-hole states for N2 physisorbed on graphite has been investigated. In the photoemission spectrum only the ionic \s~^ state is observed. The Auger spectrum shows decay from both this ionic and a neutral I5 ~' I;r^ intermediate state created by charge transfer from the substrate. The neutralization occurs with a characteristic time TCT==9X 10"'^ S. The coupling with the substrate is weak, preserving the gas phase triplet-singlet splitting of the neutral intermediate state.

The physical and electronic structure of the dispersed and (2ϫ2) phases of K/graphite have been characterized by valence and core-level photoemission. Charge transfer from K to graphite is found to occur at all coverages, and includes transfer of charge to the second graphite layer. A rigid band description is reasonably successful in describing important aspects of the data, and our results are consistent with a shift of approximately 0.4 eV in the surface graphite layer for both phases. The C 1s line shape and binding-energy shift as a function of charge transfer can be understood qualitatively by taking into account rigid band effects and the effects of a core hole on the density of states. For the ͑2ϫ2͒ phase the metallic overlayer contributes extrinsic satellites to the C 1s line shape. The K 3p spectrum is strongly affected by the overlayer phase, and in addition indicates very little variation in the substrate charge distribution as a function of coverage in the dispersed phase. The lack of an interface K 3p binding-energy shift for a K bilayer or multilayer is ascribed to a weak K-graphite bond for metallic overlayers. The results have implications for the interpretation of photoelectron spectra of alkali graphite intercalation compounds ͑GIC's͒. ͓S0163-1829͑99͒09111-0͔