1. Department of Chemistry, Visva-Bharati University, Santiniketan 731235, India
2. Department of Physics, Jadavpur University, Kolkata-700032, India
3. Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany
4. School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, West Bengal 700032, India