1. Department of Physics and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
2. Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, D-12489 Berlin, Germany
3. Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
4. Helmholtz Center München, Postfach 1129, 85664 Neuherberg, Germany
5. Institute for Organic Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14, Mainz 55099, Germany