1. Laboratory for Extraterrestrial Physics, Code 690, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
2. Department of Physics, The Catholic University of America, Washington, DC 20064, USA.
3. Department of Chemistry and Physics, Rowan University, Glassboro, NJ 08028, USA.
4. Department of Physics, Iona College, New Rochelle, NY 10801, USA.
5. Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN 46556, USA.
6. Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095–1562, USA.
7. Department of Physical Sciences, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5.