1. Contribution from the Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Canada K1A 0R6, Department of Physical Chemistry, Faculty of Chemistry, University of Santiago de Compostela, 15706 Santiago de Compostela, Spain, Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St., Cambridge Massachusetts 02138, and Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, 1101 University Avenue, Madison, Wisconsin...