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A: Atomphysik
A 4: Clusters I: Metal Clusters (joint session A and MO)
A 4.9: Talk
Monday, April 2, 2001, 17:45–18:00, H1012
From small clusters to metal spheres: photoelectron spectroscopy of Al10−10000− — •Margarita Astruc Hoffmann, Gert Wrigge, Bernd v.Issendorff, and Hellmut Haberland — Fakultät für Physik, Universität Freiburg, H.Herderstr.3, 79104 Freiburg
Aluminum cluster anions have been investigated using UV-photoelectron spectroscopy (hν = 5.0 and 6.4 eV). For the small clusters (n<200) we observed well resolved structures , which can be used to test the occurrence of electron shell closings as predicted by the jellium model. At low laser intensities larger clusters exhibit only structureless spectra. At higher laser intensities staircase like spectra are obtained, which are due to the detachment of several electrons from the same cluster. These electrons come from neutral, singly and multiply positively charged clusters. This observation of several thresholds in one spectrum allows us to study the size dependency of electron affinity and ionization potentials as a function of cluster size.