1. SORST, Japan Science and Technology Agency, c/o NEC Corporation, 34 Miyukigaoka, Tsukuba 305-8501, Japan, Department of Chemistry, Faculty of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan, Department of Chemistry, NEC Corporation, 34 Miyukigaoka, Tsukuba 305-8501, Japan, 152 Davey Laboratory, Pennsylvania State University, University Park, Pennsylvania 16802, and Department of Physics, Meijo University, 1-501 Shiogamaguchi, Tenpaku, Nagoya 468-8502, Japan