1. Dipartimento di Chimica, Università di Torino, via Giuria 5, 10125 Torino, Italy
2. Université de Lille, CNRS, UMR 8523 ─ PhLAM ─ Physique des Lasers, Atomes et Molécules, 59000 Lille, France
3. Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States