1. Department of Physics; Mangalore University; Mangalagangotri 574 199 Karnataka India
2. Department of Physics; Karnatak University; Dharwad 580 003 Karnataka India
3. Applied Nuclear Physics Division; Saha Institute of Nuclear Physics; Bidhannagar Kolkata 700 064 West Bengal India
4. Department of Chemistry; Mangalore University; Mangalagangotri 574 199 Karnataka India