1. Departement of Chemistry, University of Sassari, Via Vienna 2, 07100 Sassari (SS), Italy
2. Department of Chemistry and CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
3. CEA Saclay, DSM/IRAMIS/SIS2M/LIONS, UMR CEA-CNRS 3299, 91191 Gif-sur-Yvette, France
4. Abteilung Biophysik, Institut für Experimentelle Physik, Otto-von-Guericke Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany