[1] Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA
[2] NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Planetary Syst Lab, Greenbelt, MD 20771 USA
[3] Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA
[4] Rowan Univ, Dept Chem & Phys, Glassboro, NJ 08028 USA
[5] Univ Missouri, Dept Phys & Astron, St Louis, MO 63121 USA
[6] Univ Toledo, Dept Phys & Astron, Ritter Astronphys Res Ctr, Toledo, OH 43606 USA
[7] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA
[8] Univ New Brunswick, Dept Phys Sci, Ctr Laser Atom & Mol Sci, St John, NB E2L 4L5, Canada