1. Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
2. Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt, Germany
3. Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), Université Libre de Bruxelles, B-1050 Brussels, Belgium
4. Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium