1. Department
of Chemistry, University of California at Berkeley, Berkeley, California 94720-3220, United States
2. Department
of Physics, University of California at Berkeley, Berkeley, California 94720-7300, United States
3. Magnetic Resonance Research
Centre, Department of Chemical
Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, U.K.
4. Institute
for Technical and Macromolecular Chemistry, RWTH Aachen University, 52062 Aachen, Germany
5. Helmholtz
Institute Mainz, Johannes Gutenberg University, 55099 Mainz, Germany
6. Materials
Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-3220, United States