1. Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
2. Bruker Biospin, 15 Fortune Drive, Billerica, Massachusetts 01821, United States
3. Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
4. National High Magnetic Field Laboratory, University of Florida, Gainesville, Florida 32310, United States