1. Dipartimento di Chimica, Università di Torino, via Giuria 5, 10125 Torino, Italy
2. Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
3. Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
4. Laboratoire de Physique des Lasers et des Molecules, UFR de Physique,
Batiment P5, Universite de Lille, 59655 Villeneuve D’Ascq Cedex, France