1. Department of Physics, University Kassel, D-34109 Kassel, Germany, E-mail:
2. The Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
3. Heron's Reach, 382 Mossy Lea Road, Wrightington, Lancashire, WN6 9RZ UK
4. Kernchemie, Philipps University, D-35041 Marburg, Germany