1. Department of Chemistry and Pharmacy
2. University of Sassari
3. 07100 Sassari
4. Italy
5. Nonlinear Physical Chemistry Unit
6. Service de Chimie Physique et Biologie Théorique
7. Université libre de Bruxelles (ULB)
8. 1050 Brussels
9. Belgium
10. Department of Chemistry and Biology
11. University of Salerno
12. 84084 Fisciano