1. Department of Physics, J. T. College, Gadag 582102, Karnataka, India
2. Department of Physics, Visvesvaraya Technological University, Belgavi 590018, Karnataka, India
3. Department of Physics, M S Ramaiah Institute of Technology, Bangalore 560054, Karnataka, India
4. Department of Chemistry, RV College of Engineering, Bangalore 560059, Karnataka, India
5. Department of Physics, KLE S K Arts and H S K Science Institute, Hubballi 580031, Karnataka, India
6. Department of Physics, B V B College of Engineering and Technology, Hubli 580031, Karnataka, India
7. Department of P.G. Studies in Physics, J. T. College, Gadag 582102, Karnataka, India