1. Nanomaterials Research Institute (NMRI), National Institute of Advanced Industrial Science and Technology (AIST), Higashi 1-1-1, Tsukuba 305-8565, Japan
2. Department of Mathematics, Ohio State University, Columbus, Ohio 43201, USA and Chitrakut Annexe, 4th Main Road, Malleswaram, Bangalore 560012, India
3. Institute of Molecular Science, Okazaki, Aichi 444, Japan and Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India