1. Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Malaysia
2. Department of Petroleum, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
3. Department of Chemistry, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia