1. Department of Mathematics and Physics “E. De Giorgi” University of Salento 73100 Lecce Italy
2. CNR NANOTEC – Istituto di Nanotecnologia 73100 Lecce Italy
3. CNR – Istituto di Cristallografia 70126 Bari Italy
4. CNR – ISM Istituto di Struttura della Materia 00133 Rome Italy
5. Department of Chemistry University of Bari 70126 Bari Italy
6. Department of Chemistry and INSTM University of Pavia 27100 Pavia Italy
7. CNR NANOTEC - c/o Dipartimento di Chimica Università di Bari 70126 Bari Italy