1. Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
2. Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, United Kingdom
3. Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
4. Institut für Theoretische Physik, Goethe-Universität, Frankfurt am Main 60438, Germany
5. Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada