1. CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India
2. Department
of Physics, M K Bhavnagar University, Bhavnagar 364001, Gujarat, India
3. Department
of Physics, The M S University of Baroda, Vadodara 390002, Gujarat, India