1. Department of Chemistry, Gebze Technical University, Gebze, Kocaeli, 41400 Turkey
2. Institute of Physics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
3. Department of Physics, Gebze Technical University, Gebze, Kocaeli, Turkey
4. Institute of Applied Physics, MD-2028, Chisinau, Moldova