1. Department of Physics, Manonmanium Sundaranar University, Abishekapatti, India
2. Department of Physics and Research Centre, Nesamony Memorial Christian College, Marthandam, India
3. Department of Physics, Centre for Molecular and Biophysics Research, Mar Ivanios College, Thiruvananthapuram, India
4. Department of Physics, NSS College, Ottapalam, India