1. Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
2. Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique, 45071 Orléans, France
3. Le Studium Loire Valley Institute for Advanced Studies, 1 Rue Dupanloup, 45000 Orléans, France
4. Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States