1. Department of Physics, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa 223-8522, Japan, Advanced Energy Utilization Division, Institute of Advanced Energy, Kyoto University, Uji-shi, Kyoto 611-0011, Japan, Department of Theoretical Studies, Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan, and Department of Functional Molecular Science, The Graduate University for Advanced Studies, Okazaki, Aichi 444-8585, Japan