1. Department of Chemistry, Ankara University, 06100 Tandoǧan-Ankara, Turkey
2. Department of Chemistry, Kırıkkale University, Kırıkkale, Turkey
3. Department of Physics, Hacettepe University, 06800 Beytepe-Ankara, Turkey
4. Department of Physics, Sakarya University, 54187 Esentepe-Adapazarı, Turkey
5. Department of Chemistry, Atatürk University, 25240 Erzurum, Turkey