1. Physics Department, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
2. Deutsches Museum, Museumsinsel 1, 80538 Munich, Germany
3. Istituto di Struttura della Materia-CNR (ISM-CNR), Via Fosso del Cavaliere 100, Roma, Italy
4. Department of Physics, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133, Roma, Italy
5. Istituto Officina dei Materiali Consiglio Nazionale delle Ricerche, S.S. 14, km 163.5, Trieste, 34149, Italy
6. Department of Chemical and Pharmaceutical Sciences, Università degli Studi di Trieste, via L. Giorgieri 1, 34100, Trieste, Italy
7. Center of Micro and Nanochemistry and (Bio)Technology, Organische Chemie I, Universität Siegen, Adolf-Reichwein-Str. 2, 57068 Siegen, Germany
8. Linköping University, Department of Physics, Chemistry and Biology, IFM, 581 83 Linköping, Sweden