1. Dipartimento di Fisica “Aldo Pontremoli”, Universitá degli Studi di Milano, Via Celoria 16, Milan, Italy
2. European Theoretical Spectroscopy Facilities,
3. Department of Chemistry, The George Washington University, Washington, DC 20052, USA
4. Catalan Institute of Nanoscience and Nanotechnology - ICN2 (CSIC and BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
5. Department of Physics, Universität Osnabrück, 49076 Osnabrück, Germany
6. Chemistry Department, Debye Institute for Nanomaterials Science, Condensed Matter and Interfaces, Utrecht University, PO Box 80 000, 3508 TA Utrecht, The Netherlands