1. Department
of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
2. Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog Weg 2, 8093 Zürich, Switzerland
3. Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway