1. Petrochemicals Research Laboratory, Sumitomo Chemical, 2-1 Kitasode, Sodegaura, Chiba 299-0295, Japan.
2. Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
3. The Institute for Solid State Physics, The University of Tokyo, Tokai, Naka-gun, Ibaraki 319-1106, Japan.