1. National Petrochemical Technology Center (NPTC) Materials Science Research Institute (MSRI) King Abdulaziz City for Science and Technology (KACST), P. O. Box 6086 Riyadh 11442 Saudi Arabia
2. Department of Chemical & Process Engineering Technology Industrial Chemistry Major Jubail Industrial College Jubail Industrial City, P. O. Box 10099 31961 Saudi Arabia
3. Department of Chemistry & Industrial Chemistry College of Applied & Industrial Sciences University of Bahri Khartoum Sudan
4. Department of Physics Faculty of Science University of Ha'il P. O. Box 2440 Ha'il 81451 Saudi Arabia
5. Department of Chemistry School of Natural Sciences National University of Science and Technology, H-12 Islamabad 44000 Pakistan
6. Department of Chemistry University College London 20 Gordon Street London WC1H 0AJ United Kingdom