1. Department of Physics, Indian Institute of Technology (BHU), Varanasi 221005, India
2. Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
3. Department of Physics, The University of Burdwan, Burdwan 713104, India
4. Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, India