Affiliation: | 1.Laboratory for Atomic Molecular Spectroscopy and Applications, Faculty of Science,University Tunis El Manar,Tunis,Tunisia;2.Centre for Atomic Molecular Physics and Quantum Optics, Faculty of Science,University of Douala,Douala,Cameroon;3.Faculty of Fundamental and Applied Sciences,University of Ndjamena,Ndjamena,Chad;4.Department of Physics, Advanced Teachers Training College,University of Yaounde I,Yaounde,Cameroon |