1. Institute for Nuclear Study, University of Tokyo, Tanashi, Tokyo 188, Japan
2. Department of Chemistry, Kanazawa University, Kanazawa, Ishikawa 920-11, Japan
3. Department of Chemistry, Nagoya University, Nagoya, Aichi 464-01, Japan
4. School of Economics, Otemon Gakuin University, Ibaragi, Osaka 567, Japan
5. College of Humanities and Sciences, Nihon University, Setagaya-ku, Tokyo 156, Japan
6. Research Center for Nuclear Science and Technology, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan