[1] Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
[2] High Magnetic Field Laboratory, LANL, Los Alamos, NM 87545, United States
[3] Dept. of Mat. Sci. and Engineering, Sci. Univ. of Tokyo in Yamaguchi, Yamaguchi 756, Japan
[4] Institute of Molecular Science, Okazaki 444-8585, Japan
[5] Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
[6] Department of Chemistry, School of Science, University of Tokyo, Hongo, Tokyo 113-0033, Japan