1. Inorganic Chemistry II, Ruhr-University Bochum, 44801 Bochum, Germany
2. Experimental Physics II, Ruhr-University Bochum, 44801 Bochum, Germany
3. Fachbereich Physik and CENIDE, Universität Duisburg-Essen, Lotharstr 1, D-47057 Duisburg, Germany
4. Dynamitron-Tandem-Laboratorium (DTL) of RUBION, Ruhr-University Bochum, 44801 Bochum, Germany