1. Institute for Chemical Research Kyoto University Gokasho Uji Kyoto 611‐0011 Japan
2. Faculty of Engineering Niigata University Ikarashi Niigata 950‐2181 Japan
3. Center for Spintronics Research Network Institute for Chemical Research Kyoto University Uji Kyoto 611‐0011 Japan
4. Department of Physics Graduate School of Science Kyoto University Kyoto 606‐8502 Japan
5. Institute for Molecular Science Okazaki 444‐0867 Japan
6. Center for Spintronics Research Network Graduate School of Engineering Science Osaka University Toyonaka 560‐0043 Japan