1. Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
2. Institut de Physique et Chimie des Matériaux
de Strasbourg and Labex NIE, University of Strasbourg, CNRS UMR 7504, 67034 Strasbourg Cedex 2, France
3. Equipe de Chimie Inorganique, ICMMO (CNRS,
UMR 8182, Université Paris-Sud), Orsay F-91405, France
4. National Institute of Science Education and Research, Institute of Physics
Campus, Sachivalaya Marg, Sainik School, Bhubaneswar, Orissa 751 005, India