Berlin 2005 – scientific programme

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MO: Molekülphysik

MO 22: Poster I

MO 22.10: Poster

Saturday, March 5, 2005, 10:30–12:30, Poster HU

Influence of size and composition on the reaction kinetics of binary gold-silver cluster anions in an rf-ion trap — •Denisia Popolan, Jan Hagen, Liana D. Socaciu, Mihai E. Vaida, Bruno S. Schmidt, Thorsten M. Bernhardt, and Ludger Wöste — Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany

Small metal clusters were subject of many experimental and theoretical investigations in the last decade because of their fascinating size-dependent physical and chemical properties, which differ significantly from those of the atom and the bulk. The investigation of small charged clusters in the gas phase may even add to an understanding of catalytic reaction mechanisms. In contrast to the extensively studied electronic and structural properties of pure gold and silver clusters in the gas phase and on surface, considerably less information is available about the bimetallic silver-gold clusters, although supported bimetallic particles are promising candidates for industrial heterogeneous catalysis. In this context, we have investigated the reactive behaviour of binary Ag_nAu_m⁻ clusters in an rf-ion trap setup. It was found that AuAg⁻ reacts with O₂ reactive gas, and remains inert against CO. Surprisingly, the mixed silver-gold trimers present non-reactive character toward both, O₂ and CO. A comparison between reaction behaviour of pure Ag_n⁻ , Au_m⁻ and mixed Ag_nAu_m⁻ in the presence of O₂ and CO reactive gas will be presented.