1. Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi‐ku, Osaka 558‐8585 (Japan), Fax: (+81) 6‐6605‐2568
2. Department of Physical Science, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599‐8531 (Japan)
3. Research Center for Structural Themodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560‐0043 (Japan), Fax: (+81) 6‐6850‐5526