1. Institut für Physikalische und Theoretische Chemie, Universität Bonn, D-53115 Bonn, Germany
2. National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310
3. Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
4. Department of Chemistry, National Chung Cheng University, Chia-Yi 621, Taiwan
5. Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
6. Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan