1. Department of Physics; Janata Mahavidhyalaya Chandrapur 442401 India
2. Department of Chemistry; Sevadal Mahila Mahavidyalaya Nagpur 440009 India
3. Faculty of Nanotechnology and Advanced Materials Engineering; Sejong University; Seoul 143-747 Korea
4. N.H. College; Bramhapuri 441206 India
5. Department of Physics; R.T.M. Nagpur University; Nagpur 440033 India