1. Department of Physics, Mangalore University, Mangalagangotri, Mangalore, Karnataka, India
2. Department of Physics, Karnatak University, Dharwad, Karnataka, India
3. Department of Chemistry, Mangalore University, Mangalagangotri, Mangalore, Karnataka, India
4. Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India