Affiliation: | 1. Physics Department, Faculty of Science, University of Hail, Saudi Arabia;2. Faculté des Sciences de Tunis, Universite de Tunis El Manar, Tunis, Tunisia;3. Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada;4. On leave from Laboratoire de Physique Quantique, Faculté des Sciences de Monastir, 5019 Monastir, Tunisia |