1. Department of Chemistry “Ugo Schiff” and CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
2. Department of Physics, University of Genoa, Genoa 16146, Italy
3. Institute of Inorganic Chemistry, Graz University of Technology, 8010 Graz, Austria
4. European Laboratory for Non-Linear Spectroscopy (LENS), 50019 Sesto Fiorentino, Italy