1. Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
2. Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201, United States
3. Laboratory of Biomolecular NMR, St. Petersburg State University, St. Petersburg 199034, Russia
4. Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
5. Graduate School of China Academy of Engineering Physics, Beijing 100193, China
6. Department of Physics, University of Arizona, Tucson, Arizona 85721, United States