1. Photodynamics Research Center, RIKEN (The Institute of Physical and Chemical Research), 519-1399, Aoba, Aramaki, Aoba-ku, Sendai 980-0845, Japan, Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan, and Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616