1. Department of Chemistry; Yuvaraj's College, University of Mysore; Mysore 570 006 India
2. Department of Polymer Science and Technology; Sri Jayachamarajendra College of Engineering; Mysore 570 006 India
3. Department of Physics and Research Centre; Sambhram Institute of Technology; Bangalore 560 097 India
4. Department of Studies in Physics; University of Mysore, Manasagangotri; Mysore 570 006 India