1. Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089
2. Department of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487-0336
3. Department of Chemistry, University of California, Riverside, California 92521
4. Space and Missile Propulsion Division, Air Force Research Laboratory (AFRL/RZS), Edwards Air Force Base, California 93524