1. Department of Physical Chemistry, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland, CNRS, Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, UMR 8587, Université d’Evry Val d’Essonne, Boulevard F. Mitterrand, 91025 Evry Cedex, France, and Department of Chemistry and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States