1. National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044,
Japan
2. Department
of Chemistry, Gakushuin University, 1-5-1 Mejiro,
Toshima-ku, Tokyo 171-8588, Japan
3. Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho
679-5198, Japan
4. Institute
of Materials Structure
Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan