1. 1Faculty of Integrated Arts and Sciences, Tokushima University, Minamijosanjima-cho, Tokushima 770, Japan
2. 2Department of Chemistry, Faculty of Education, Saga University, Honjo-machi 1, Saga 840, Japan
3. 3Department of Chemistry, Faculty of Science, Hiroshima University, Kagamiyama, Higashihiroshima 724, Japan
4. 4Institut für Physikalische Chemie, Physikalische Chemie III, Technische Hochschule Darmstadt, Petersenstr. 20, D-6100 Darmstadt, Germany