1. Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan, Bruker Biospin K. K., Tsukuba, Ibaraki 305-0051, Japan, Department of Theoretical Molecular Science, Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan, and University of Houston, Houston, Texas 77204-5003