title: Desorption of Oxygen from Cationic Niobium Oxide Clusters Revealed by Gas Phase Thermal Desorption Spectrometry and Density Functional Theory Calculations.
abstract: Thermal dissociation of cationic niobium oxide clusters (NbnOm+) was investigated by gas phase thermal desorption spectrometry. The dominant species formed at 300 K were NbnO(5/2)n+p+(n = 2, 4, 6, ...; p = 0, 1, 2, ...) and NbnO((5/2)n-1/2)+q+(n = 3, 5, ...; q = 0, 1, 2, ...). At higher temperatures, the more oxygen-rich clusters were observed to release O2. However, the desorption of O2from NbnOm+was found to be insignificant in comparison with VnOm+because Nb tends to have a +5 oxidation state exclusively, whereas V can have both +4 and +5 oxidation states. The propensity for the release of O atoms was manifested in the formation of NbnO(5/2)n-1/2+from NbnO((5/2)n-1/2)+1+for odd values of n, whereas VnO((5/2)n-1/2)+1+released O2molecules instead. The energetics of the O and O2release from the Nb and V oxide clusters, respectively, was consistent with the results of DFT calculations.
authors.affiliation: Department of Basic Science, School of Arts and Sciences, The University of Tokyo , Komaba, Meguro, Tokyo 153-8902, Japan.
authors.forename: Daigo
authors.initials: D
authors.lastname: Masuzaki
authors.affiliation: Department of Basic Science, School of Arts and Sciences, The University of Tokyo , Komaba, Meguro, Tokyo 153-8902, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nagata
authors.affiliation: Department of Basic Science, School of Arts and Sciences, The University of Tokyo , Komaba, Meguro, Tokyo 153-8902, Japan.
authors.forename: Fumitaka
authors.identifier: http://orcid.org/0000-0001-8860-6354
authors.initials: F
authors.lastname: Mafuné