Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 73: Symposium: Bimetallic Nanosystems: Tuning Physical and Chemical Properties II (Invited Speakers: André Fielicke, Thomas Risse, Jürgen Behm)
O 73.1: Hauptvortrag (ohne Erstattung)
Donnerstag, 28. Februar 2008, 14:00–14:30, MA 005
Doped clusters in light of an IR-FEL — •André Fielicke1, Philipp Gruene1, Gerard Meijer1, Ewald Janssens2, Vu Thi Ngan2, Minh Tho Nguyen2, and Peter Lievens2 — 1Fritz-Haber-Institut der MPG, Berlin — 2University of Leuven, Belgium
Changing the composition of a metal cluster naturally will alter its physical and chemical properties; however, often these changes are not gradual but lead to very different and unexpected behavior. In the last years several of such mixed cluster systems have been predicted by theory and also identified in experiments to exhibit unusual stabilities. In many cases this stabilization is supposed to be related to the formation of structures that are stabilized by both, electronic and geometrical effects. We focus on the determination of the geometrical structure of such isolated clusters in the gas-phase via vibrational spectroscopy. Cluster complexed with weakly bound ligands, i.e. rare gas atoms, are irradiated with intense and tunable far-IR radiation from the Free Electron Laser for Infrared eXperiments FELIX. Absorption leads to a heating of the cluster and subsequent evaporation of the ligand. This process is observed via mass spectrometry that allows determining the clusters far-IR spectra size and composition selectively. The influence of doping on the structural properties will be exemplified for silicon and gold clusters doped with transition metal atoms.