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MO: Fachverband Molekülphysik
MO 7: Poster: Cluster
MO 7.1: Poster
Montag, 14. März 2011, 16:00–18:00, P1
Autoionization processes in homogeneous and heterogeneous clusters — •Tiberiu Arion1, Melanie Mucke1, Marko Förstel1, Hans-Peter Rust1, Alexander M. Bradshaw1,2, and Uwe Hergenhahn1 — 1Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching, Germany — 2Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
Experimental investigations of Interatomic/Intermolecular Coulombic Decay have gained considerable momentum in the last few years. We have investigated this novel autoionization process by electron and e−,e− coincidence spectroscopy, using a magnetic bottle spectrometer. We have revisited ICD in medium-sized homogeneouos Ne clusters, and find a minimum kinetic energy of ICD of around 0.8 eV, different from earlier experiments on the Ne dimer. In heterogeneous clusters of Ne and Kr we have recorded an unusually high transition energy of about 10 eV. Here, the ICD process proceeds after Ne 2s photoionization, and leaves a final state with a Ne 2p−1 and a Kr 4p−1 vacancy. We have studied the dependence of the effect on photon energy, cluster composition and cluster size. Interestingly, the ICD electron energy increases slightly and grows a shoulder on going from 2 % to 5 % Kr in the co-expansion process, which we interpret in terms of surface vs. bulk effects. We have performed similar experiments on ArXe mixed clusters, where the ICD electron is expected to have a kinetic energy in the 0-2 eV range. Extending our earlier study on water clusters, we have also recently investigated ICD in water clusters as a function of the size of the cluster as well as of isotopic substitution.