1. Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
2. Department of Physics, Faculty of Science, University of Tabuk, Tabuk, Saudi Arabia
3. Department of Polymer Engineering, University of Chemical Technology and Metallurgy, Sofia, Bulgaria
4. Department of Chemistry, Technical University, Sofia, Bulgaria
5. Department of Wireless communications and broadcasting, College of Telecommunications and Posts, Sofia, Bulgaria
6. Department of Physics, Faculty of Science, Suez Canal University, Ismailia, Egypt