1. Department
of Physics, University of Pavia, 27100 Pavia, Italy
2. NMR
Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
3. Department
of Chemistry, Materials, and Chemical Engineering G. Natta, Politecnico di Milano, 20133 Milano, Italy