1. Department of Chemistry, Shelby Hall, P.O. Box 870336, University of Alabama, Tuscaloosa, Alabama 35487-0336
2. William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352
3. Department of Chemistry, Washington State University, Pullman, Washington 99164-4630
4. Department of Chemistry, University of Waterloo, Waterloo, ON, N2G 4V2, Canada