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A: Atomphysik

A 13: Photoionisation

A 13.1: Hauptvortrag

Mittwoch, 15. März 2006, 14:00–14:30, H7

Photoelectron spectroscopy of large sodium clusters — •Bernd v.Issendorff — Fakultät für Physik, Universität Freiburg, Stefan Meier Str. 21, 79104 Freiburg, Germany

Small simple metal particles are fascinating quantum objects; many of their properties can be understood in a No-dqsuperatomNo-dq picture, which assumes atom-like delocalized electron wavefunctions. This makes them ideal model systems for, e.g., the study of the dynamics of a finite fermion system. For this purpose it is of course necessary to characterize the electron system of the clusters as closely as possible. Therefore cold size selected sodium cluster anions have been studied in a very broad size range (N=3-3000) by photoelectron spectroscopy. The results are in overall good agreement with the free electron model, but exhibit a decisive influence of the cluster geometry as well. Icosahedral symmetry was found to prevail in the size range at least up to N=400. Additionally precise values of the cluster charging energies could be extracted from the spectra, which constitute a good general test for theoretical calculations. Finally new measurements of the angular distribution of the photoelectrons are dicussed, which give detailed information about the character of the electron wavefunctions in the cluster.