1. Department of Chemistry, Faculty of Science, Toho University, Miyama, Funabashi, Chiba 274-8510, Japan, Department of Physics, Faculty of Science, Toho University, Miyama, Funabashi, Chiba 274-8510, Japan, and Institute for Solid State Physics, The University of Tokyo, Kashiwanoha, Kashiwa-shi, Chiba 277-8581, Japan