Darmstadt 2008 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 7: Metal clusters

A 7.1: Hauptvortrag

Dienstag, 11. März 2008, 11:00–11:30, 3D

Vibrational spectroscopy of isolated metal clusters with a Free Electron Laser — •André Fielicke, Philipp Gruene, Jonathan T. Lyon, and Gerard Meijer — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin

Small particles often differ considerably in their properties from the bulk material. This has triggered a large interest in the study of matter on the nano-scale, but the basic determination of the structures of nano-materials on an atomic scale can be exceedingly difficult. However, knowing the atomic arrangements of the clusters is one of the crucial ingredients that is needed for understanding their physical and chemical properties. Particularly sensitive to the internal cluster structure is vibrational spectroscopy, since it directly maps the bonding forces and, in its appropriate variant, it is susceptible to the cluster symmetry. We have recently demonstrated far-infrared multiple photon dissociation (far-IR-MPD) spectroscopy on transition metal cluster rare-gas complexes as a method to obtain the vibrational spectra in the range of their structure-specific vibrational fundamentals. The intense and tunable far-IR radiation needed for this is delivered by the Free Electron Laser for Infrared eXperiments FELIX. IR-MPD spectroscopy on the metal-cluster rare-gas complexes combined with quantum chemical calculations allows for the determination of the cluster structures. As examples we will discuss the growth behaviour of clusters of the group 5 transition metals (V, Nb, Ta) and of pure and doped silicon clusters.