1. Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8502, Materials and Structures Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8503, Institute for Molecular Science, Myodaiji, Okazaki 444-8787, NHK Science and Technical Research Laboratories, Kinuta, Setagaya-ku, Tokyo 157-851, Japan