1. Department
of Chemistry and Chemical Technologies, University of Calabria, via P. Bucci, Cubo 14D, 87036 Rende (CS), Italy
2. Department
of Material Science and Engineering, University of Ioannina, 45110 Ioannina, Greece
3. Department
of Science, University of Basilicata, V.le Ateneo Lucano 10, 85100 Potenza (PZ), Italy
4. Department
of Physics, University of Calabria, via P.Bucci, Cubo 31 C, 87036 Rende (CS), Italy
5. CNR-ITAE Institute, via Salita
S. Lucia sopra Contesse, 5, 98126 Messina, Italy