1. Department of Physics, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
2. Department of Natural Sciences, University of Michigan − Dearborn, 4901 Evergreen Rd, Dearborn, Michigan 48128-1491, United States
3. Department of Chemistry, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus