1. Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada, Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada, and Sandia National Laboratories, MS 1349, Albuquerque, New Mexico 87185 and Center for Micro-Engineered Materials, University of New Mexico, Albuquerque, New Mexico 87131