1. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
2. National Radio Astronomy Observatory, Charlottesville, VA 22903, USA.
3. Center for Astrophysics, Harvard & Smithsonian, Cambridge, MA 02138, USA.
4. Department of Physics and Astronomy, Benedictine College, Atchison, KS 66002, USA.
5. Center for Astrochemical Studies, Max Planck Institute for Extraterrestrial Physics, Garching, Germany.
6. Institute for Theoretical Chemistry, University of Stuttgart, Stuttgart, Germany.
7. Astrochemistry Laboratory and the Goddard Center for Astrobiology, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
8. Université de Rennes, Centre National de la Recherche Scientifique, Institut de Physique de Rennes, Unité Mixte de Recherche 6251, F-35000 Rennes, France.
9. Institute for Astrophysics and Computational Sciences, Department of Physics, Catholic University of America, Washington, DC 20064, USA.
10. Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
11. Department of Astronomy, University of Virginia, Charlottesville, VA 22904, USA.
12. Astro Space Center, Lebedev Physical Institute, Russian Academy of Sciences, Moscow, Russia.