1. Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6, Institute for Microstructural Sciences, National Research Council of Canada, M50-263, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6, and Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5