1. PG & Research Department of Physics, Arignar Anna Government Arts College, Cheyyar, Tamil Nadu 604 407, India
2. Thiruvalluvar University, Serkkadu, Vellore, Tamil Nadu 632 115, India
3. Department of Physics, Government College of Engineering, Bargur, Tamil Nadu 635 104, India
4. Department of Chemistry, Government College of Engineering, Bargur, Tamil Nadu 635 104, India