1. Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
2. Space and Missile Propulsion Division, Air Force Research Laboratory (AFRL/RZS), Edwards Air Force Base, California 93524, United States
3. Department of Chemistry, University of Warwick, Coventry CV4 7AL, West Midlands, U.K.
4. Department of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487-0336, United States