title: Gas phase vibrational spectroscopy of cold (TiO2)n(-) (n = 3-8) clusters.
abstract: We report infrared photodissociation (IRPD) spectra for the D2-tagged titanium oxide cluster anions (TiO2)n(-) with n = 3-8 in the spectral region from 450 to 1200 cm(-1). The IRPD spectra are interpreted with the aid of harmonic spectra from BP86/6-311+G* density functional theory calculations of energetically low-lying isomers. We conclusively assign the IRPD spectra of the n = 3 and n = 6 clusters to global minimum energy structures with Cs and C2 symmetry, respectively. The vibrational spectra of the n = 4 and n = 7 clusters can be attributed to contributions of at most two low-lying structures. While our calculations indicate that the n = 5 and n = 8 clusters have many more low-lying isomers than the other clusters, the dominant contributions to their spectra can be assigned to the lowest energy structures. Through comparison between the calculated and experimental spectra, we can draw conclusions about the size-dependent evolution of the properties of (TiO2)n(-) clusters, and on their potential utility as model systems for catalysis on a bulk TiO2 surface.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Marissa L
authors.initials: ML
authors.lastname: Weichman
authors.affiliation: Fritz-Haber-Institut der Max-Plank-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Song
authors.affiliation: Fritz-Haber-Institut der Max-Plank-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Matias R
authors.initials: MR
authors.lastname: Fagiani
authors.affiliation: Fritz-Haber-Institut der Max-Plank-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Sreekanta
authors.initials: S
authors.lastname: Debnath
authors.affiliation: Fritz-Haber-Institut der Max-Plank-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Sandy
authors.initials: S
authors.lastname: Gewinner
authors.affiliation: Fritz-Haber-Institut der Max-Plank-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Wieland
authors.initials: W
authors.lastname: Schöllkopf
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Neumark
authors.affiliation: Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany.
authors.forename: Knut R
authors.initials: KR
authors.lastname: Asmis