1. P.G. and Research Department of Physics, AVVM Sri Pushpam College (Autonomous), Poondi; Thanjavur 613503 Tamil Nadu India
2. Research Department of Physics, Kunthavai Naachiyaar Government Arts College for Women (Autonomous); Thanjavur 613007 Tamil Nadu India
3. CUER-UL, Université de Lomé; BP 1515, Lomé Togo