1. Contribution from the Advanced Materials Laboratory, Sandia National Laboratories, Albuquerque, New Mexico 87106, Departments of Chemistry, Chemical and Nuclear Engineering, and Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, CEQUP/Departamento de Quimica, Faculdade de Ciencias, Universidade do Porto, Porto, Portugal, and Department of Chemistry, University of Georgia, Athens, Georgia 30602