Stuttgart 2012 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 8: Ion Trap and FT-ICR-MS, Molecules, Clusters and Reactions
MS 8.1: Hauptvortrag
Donnerstag, 15. März 2012, 14:00–14:30, V57.06
Structure and dynamics of finite Fermi systems: simple metal clusters and fullerenes — •Bernd v. Issendorff — Physikalisches Institut, Universität Freiburg, 79104 Freiburg
Of all metallic systems sodium clusters are the ones which are closest to the ideal case of a finite free electron gas. Their electronic density of states is strongly discretized and shows a clear similarity with the electron shell structure of a spherical free electron system, although with some perturbation caused by the usually nonspherical outer shape and the internal atomic structure of the clusters. Recently we have shown by angular resolved photoelectron spectroscopy that in spherical sodium clusters these perturbed electron states still exhibit well defined angular momentum eigenstate character. Here similar results on strongly spheroidally deformed clusters will be presented, which show that even in such cases the angular momentum eigenstate character is preserved. In fact the deformation just lifts the degeneracy of the ml-substates of a given l-state and causes a mixing between certain states which follows a strict selection rule. Fullerenes with their delocalized valence electron system are well suited for the study of electron dynamics due to their high stability. Time-resolved photoelectron spectroscopy has been applied to gas phase C60 anions of controlled temperature. The results show a strong temperature dependence of the relaxation time of the final (and slowest) process in the chain of relaxation processes of the excited excess electron, the t1g → t1u transition, which can be seen as a textbook example of the vibrational excitation dependence of a radiationless transition.