1. Dipartimento di Scienze e Tecnologie
Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
2. National Institute for Nanotechnology, National Research Council of Canada, 11421 Saskatchewan
Drive, Edmonton, Alberta T6G 2M9, Canada
3. Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1,
Canada