1. Department of Chemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
2. W.M. Keck Laboratory in Astrochemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
3. Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
4. Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States