1. Institut für Anorganische und Analytische Chemie Friedrich-Schiller-Universität Jena Humboldtstrasse 8 07743 Jena Germany
2. Department of Physics and Astronomy University of Florence and INSTM UdR via Sansone 1 Sesto Fiorentino (FI) Italy
3. Dipartimento di Chimica “Ugo Schiff” Universitá degli Studi Firenze Via della Lastruccia 3–13 50019 Sesto Fiorentino (FI) Italy
4. Current address: Institute of Physical Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany