%0 Journal Article %1 Laubach2007 %A Laubach, Stefan %A Schmidt, Peter C. %A ThiGerman sz ligature en, Andreas %A Fernandez-Madrigal, Francisco Javier %A Wu, Qi-Hui %A Jaegermann, Wolfram %A Klemm, Matthias %A Horn, Siegfried %D 2007 %I The Royal Society of Chemistry %J Phys. Chem. Chem. Phys. %K battery %N 20 %P 2564-2576 %R 10.1039/B612489E %T Theoretical and experimental determination of the electronic structure of V2O5, reduced V2O5- and sodium intercalated NaV2O5 %U http://dx.doi.org/10.1039/B612489E %V 9 %X In this work the electronic structure of VO, reduced VO (VO) and sodium intercalated NaVO has been studied by both theoretical and experimental methods. Theoretical band structure calculations have been performed using density functional methods (DFT). We have investigated the electron density distribution of the valence states, the total density of states (total DOS) and the partial valence band density of states (PVBDOS). Experimentally, amorphous VO thin films have been prepared by physical vapour deposition (PVD) on freshly cleaved highly oriented pyrolytic graphite (HOPG) substrates at room temperature with an initial oxygen understoichiometry of about 4%, resulting in a net stoichiometry of VO. These films have been intercalated by sodium using vacuum deposition with subsequent spontaneous intercalation (NaVO) at room temperature. Resonant V3p-V3d photoelectron spectroscopy (ResPES) experiments have been performed to determine the PVBDOS focusing on the calculation of occupation numbers and the determination of effective oxidation state, reflecting ionicity and covalency of the V-O bonds. Using X-ray absorption near edge spectra (XANES) an attempt is made to visualize the changes in the unoccupied DOS due to sodium intercalation. For comparison measurements on nearly stoichiometric VO single crystals have been performed. The experimental data for the freshly cleaved and only marginally reduced VO single crystals and the NaVO results are in good agreement with the calculated values. The ResPES results for VO agree in principle with the calculations, but the trends in the change of the ionicity differ between experiment and theory. Experimentally we find partly occupied V 3d states above the oxygen 2p-like states and a band gap between these and the unoccupied states. In theory one finds this occupation scheme assuming oxygen vacancies in VO and by performing a spin-polarized calculation of an antiferromagnetic ordered NaVO

@article{Laubach2007, abstract = {In this work the electronic structure of VO{,} reduced VO (VO) and sodium intercalated NaVO has been studied by both theoretical and experimental methods. Theoretical band structure calculations have been performed using density functional methods (DFT). We have investigated the electron density distribution of the valence states{,} the total density of states (total DOS) and the partial valence band density of states (PVBDOS). Experimentally{,} amorphous VO thin films have been prepared by physical vapour deposition (PVD) on freshly cleaved highly oriented pyrolytic graphite (HOPG) substrates at room temperature with an initial oxygen understoichiometry of about 4%{,} resulting in a net stoichiometry of VO. These films have been intercalated by sodium using vacuum deposition with subsequent spontaneous intercalation (NaVO) at room temperature. Resonant V3p-V3d photoelectron spectroscopy (ResPES) experiments have been performed to determine the PVBDOS focusing on the calculation of occupation numbers and the determination of effective oxidation state{,} reflecting ionicity and covalency of the V-O bonds. Using X-ray absorption near edge spectra (XANES) an attempt is made to visualize the changes in the unoccupied DOS due to sodium intercalation. For comparison measurements on nearly stoichiometric VO single crystals have been performed. The experimental data for the freshly cleaved and only marginally reduced VO single crystals and the NaVO results are in good agreement with the calculated values. The ResPES results for VO agree in principle with the calculations{,} but the trends in the change of the ionicity differ between experiment and theory. Experimentally we find partly occupied V 3d states above the oxygen 2p-like states and a band gap between these and the unoccupied states. In theory one finds this occupation scheme assuming oxygen vacancies in VO and by performing a spin-polarized calculation of an antiferromagnetic ordered NaVO}, added-at = {2012-09-17T11:11:42.000+0200}, author = {Laubach, Stefan and Schmidt, Peter C. and Thi[German sz ligature en, Andreas and Fernandez-Madrigal, Francisco Javier and Wu, Qi-Hui and Jaegermann, Wolfram and Klemm, Matthias and Horn, Siegfried}, biburl = {https://www.bibsonomy.org/bibtex/2aedaf8f5670acfefbd0368df5481f5c9/pmd}, description = {Theoretical and experimental determination of the electronic structure of V2O5, reduced V2O5− and sodium intercalated NaV2O5 - Physical Chemistry Chemical Physics (RSC Publishing)}, doi = {10.1039/B612489E}, interhash = {93cceff236dab1bec4d7231fbc314960}, intrahash = {aedaf8f5670acfefbd0368df5481f5c9}, journal = {Phys. Chem. Chem. Phys.}, keywords = {battery}, number = 20, pages = {2564-2576}, publisher = {The Royal Society of Chemistry}, timestamp = {2012-09-17T11:12:27.000+0200}, title = {Theoretical and experimental determination of the electronic structure of V2O5{,} reduced V2O5- and sodium intercalated NaV2O5}, url = {http://dx.doi.org/10.1039/B612489E}, volume = 9, year = 2007 }