1. Department of Chemistry, Kyoto University, Sakyo-ku, Kyoto 606-01
2. Department of Physics, Gakushuin University, Mejiro, Toshima-ku, Tokyo 171
3. International Superconductivity Technology Center, Nagoya Division, Mutsuno, Atsuta, Nagoya 456
4. Institute for Molecular Science, Okazaki 444