1. Department of Chemistry Graduate School of Engineering Science Osaka University Toyonaka Osaka 560‐8531 Japan
2. International Center for Materials Nanoarchitectonics (WPI‐MANA) National Institute for Materials Science (NIMS) Tsukuba Ibaraki 305‐0044 Japan
3. Department of Advanced Materials Science Graduate School of Frontier Science The University of Tokyo Kashiwa Chiba 277‐8561 Japan
4. Institute for Solid State Physics The University of Tokyo Kashiwa Chiba 277‐8581 Japan
5. Department of Chemistry San José State University San José California 95192‐0101 USA