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A: Fachverband Atomphysik
A 16: Atomic Clusters II
A 16.4: Vortrag
Mittwoch, 4. März 2009, 15:15–15:30, VMP 6 HS-B
Transition metal and silicon 2p photoionization of Ti, V, and Cr doped Sin+ cages — •Andreas Langenberg1, Marlene Vogel1, Konstantin Hirsch1, Philipp Klar1, Fabian Lofink1, Jürgen Probst1, Robert Richter1, Jochen Rittmann1, Vicente Zamudio-Bayer1, Thomas Möller1, Bernd von Issendorff2, and Tobias Lau1 — 1Technische Universität Berlin, Institut für Optik und Atomare Physik, EW 3-1, Hardenbergstr. 36, 10623 Berlin — 2Albert-Ludwigs-Universität Freiburg, Fakultät für Physik/FMF, Stefan-Meier-Str. 21, 79104 Freiburg
Silicon 2p photoionization spectroscopy of titanium, vanadium, and chromium doped Sin+ cages complements X-ray absorption studies at the transition metal 2p edges. While clusters with lower symmetry show broad bands in resonant silicon 2p photoionization, the highly symmetric TiSi16+, VSi16+, and CrSi16+ clusters are characterized by a rich line structure in their spectra. This is a further indication of a highly degenerate density of states and electronic shells in these clusters. Furthermore, resonant and direct photoionization channels are associated with different fragmentation patterns at the silicon 2p edge and can be separated ex post in ion yield spectra. This gives access to the direct photoionization threshold and even to x-ray photoelectron spectra. Compared to VSi15+ and VSi17+, the direct 2p photoionization threshold of magic VSi16+ is shifted by approx. 0.7 eV to higher photon energy because of the large HOMO-LUMO gap. We will discuss our recent results with an outlook at valence band photoionization spectroscopy of cationic clusters.