1. Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
2. ISIS Facility, Rutherford Appleton Laboratory, OX11 0QX Didcot, United Kingdom
3. Department of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark
4. Department of Chemistry, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
5. UdR Parma, INSTM, I-43124 Parma, Italy