The electronic structure of methanol covered TiO2(110) surfaces

We report on the electronic structure rutile TiO2(110) surfaces following the exposure to methanol. Two-photon photoemission (2PP) spectra reveal a strong resonance at 2.2–2.4 eV above Fermi level, which gains maximum intensity at 1 ML coverage of methanol. From the coverage, temperature and emission angle dependence of the methanol induced spectral features and similarities to a related state on water covered TiO2(110) surfaces, we assign the resonance to charge transfer excitation from the reduced five-coordinate Ti d 5c ions to hydroxyl groups on the bridging oxygen rows. 2005 Elsevier B.V. All rights reserved.