1. PG and Research Department of Physics, Bishop Heber College, Tiruchirappalli 620 017, Tamil Nadu, India
2. Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, Tamil Nadu, India
3. Department of Chemistry, M. S. Ramaiah Institute of Technology, Bangalore 560 054, Karnataka, India
4. PG and Research Department of Physics, Nehru Memorial College, Puthanampatti, Trichy 621 007, Tamil Nadu, India
5. PG and Research Department of Physics, Periyar EVR College, Tiruchirappalli 620 023, Tamil Nadu, India
6. School of Physics, Alagappa University, Karaikudi, Tamil Nadu 630 003, India