1. Department of Chemistry, University of Waterloo, Waterloo, Ontario, N2L 3G1 Canada, Department of Chemistry, University of Victoria, Victoria, BC, V8P 5C2 Canada, Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, L8S 4M1 Canada, and Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3X7 Canada