1. JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196, Japan (KM.); Department of Chemistry, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan (A.Y., Y.F., M.T.); and Nikko Kyodo Co., Ltd., Petroleum Laboratory, 3-17-35, Niizominami, Toda, Saitama 335, Japan (A. Y.)