1. Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway
2. Berkeley Center for Cosmological Physics and Department of Physics, University of California, Berkeley, California 94720, United States
3. Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States