Düsseldorf 2007 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 18: Interaction with VUV and X-Ray light
A 18.7: Vortrag
Mittwoch, 21. März 2007, 18:15–18:30, 6G
Soft X-ray Ion Yield Spectroscopy of Neutral Transition Metal Clusters — •Tobias Lau1, Jochen Rittmann1, Theresa Schadow1, Marlene Vogel1, Vicente Zamudio-Bayer1, Max Feucker1, Marko Härtelt1, Fabian Lofink1, Bernd von Issendorff2, and Thomas Möller1 — 1Technische Universität Berlin, Institut für Optik und Atomare Physik, PN 3-1, Hardenbergstraße 36, D-10623 Berlin — 2Albert-Ludwigs-Universität Freiburg, Fakultät für Physik/FMF, Stefan-Meier-Straße 21, D-79104 Freiburg
Core level spectroscopy is a valuable tool to study the local electronic density of states with element specificity. Recently, mass resolved ion yield spectra of neutral transition metal clusters after core level excitation at their L2,3 edges have been measured at BESSY. The basic concept of the experiment will be outlined and relevant details of the method will be discussed in view of first results.
The transition from atomic to bulk-like core-level excitation spectra is studied as a function of cluster size for Ti, V, Cr, Co, and Ni clusters. Preliminary analysis of L2,3 line shapes and branching ratios indicates that this transition takes place already in small transition metal clusters with a size around 50 atoms per cluster. In the X-ray absorption process, core level excitation and subsequent relaxation lead to cluster fragmentation and to multiply charged clusters. As a result, apparent changes in the cluster size distribution are observed. Cluster fragmentation and ionization are analyzed as a function of cluster size in the vicinity of the L2,3 edges.