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, Canada T6G 2M9
3. Department of Physics, University of Alberta, Edmonton, Alberta,
Canada T6G 2E1