1. Manonmaniam Sundaranar University, Tirunelveli, Tamil Nadu, India
2. Department of Physics & Research Centre, Women’s Christian College, Nagercoil, Tamil Nadu, India
3. Department of Physics & Research Centre, Nanjil Catholic College of Arts and Science, Kaliyakkavilai, Tamil Nadu, India
4. Department of Physics, Nesamony Memorial Christian College, Marthandam, Tamil Nadu, India