1. Department of Metallurgy, Graduate School of Engineering, Tohoku University, Aramaki-aza-Aoba, Aoba-ku, Sendai, 980-77, National Institute for Advanced Interdisciplinary Research/Mechanical Engineering Laboratory, AIST, 1-1-4 Higashi, Tsukuba 305, Japan, Department of Chemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08855-0939, and Kyushu Institute of Technology at Iizuka, Fukuoka 820, Japan