1. Center for Astrophysics|Harvard & Smithsonian, Atomic and Molecular Physics Division, 60 Garden Street, Cambridge, MA 02138, USA
2. Department of Chemistry, Lomonosov Moscow State University, GSP-1, 1-3 Leninskiye Gory, Moscow 119991, Russia
3. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, 3 Pyzhevsky per., Moscow 119017, Russia
4. Institute of Quantum Physics, Irkutsk National Research Technical University, 83 Lermontov str., 664074 Irkutsk, Russia
5. Department of Optics and Spectroscopy, Tomsk State University, 36 Lenin Ave., Tomsk 634050, Russia
6. Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK