1. Department of Physics, SGGS Khalsa College, Mahilpur 146 105, Punjab, India
2. Department of Physics, DAV University, Jalandhar 144012, India
3. Department of Chemistry, Jagdish Chandra DAV College, Dasuya 144 205, Punjab, India
4. Department of Physics, Jagdish Chandra DAV College, Dasuya 144 205, Punjab, India