Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Tokai, Ibaraki 319-1106, Japan, CREST, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan, and Kawamura Institute of Chemical Research, 631 Sakada, Sakura-shi, Chiba 285-0078, Japan(2006-10-21時点)
