Theoretical Chemistry Section, Chemistry Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085,
Swapan K Ghosh, BARC, Mumbai, elected to Fellowship in 1991. Ghosh’s research interests include theoretical chemistry, computational materials science and soft condensed matter physics. He is Raja Ramanna Fellow at BARC, Mumbai, Senior Professor at HBNI, Mumbai and also a Distinguished Professor at UM-DAE-Centre of Excellence in Basic Sciences, Mumbai. He is the recipient of the TWAS Prize in Chemistry from TWAS, Trieste, Italy.
Session 1D - Walter Kohn Memorial Symposium
Density functional theory for materials modelling at different length scales: A legacy of Walter Kohn
One of the concepts that has played a major role in the conceptual as well as computational developments covering different length scales of interest in a number of areas of chemistry, physics and materials science is single-particle density. The use of single-particle electron density as the basic variable was formally established by Walter Kohn et al., leading to the birth of density functional theory (DFT), which has established itself as a conceptually simple, computationally economic and versatile tool for electronic structure-based calculations and understanding of chemical binding in atoms, molecules and solids. DFT has also travelled beyond the territory of the microscopic length scale and quantum domain. Thus, in the intermediate mesoscopic length scale, which covers a wide class of problems involving nanomaterials, interfacial science and soft condensed matter, an appropriate picture of the equilibrium and dynamical processes has been obtained through the single-particle number density of the constituent particles. In the macroscopic length scale, however, one usually considers matter as a continuous medium, and a description using local mass density, energy density and other related property density functions has been found to be quite appropriate. In spite of the differences in the nature of the density variables used in all these DFT-based descriptions, the corresponding theoretical frameworks, which project the many-particle picture to a single-particle one, have been found to possess an underlying unified structure. Some of these developments and applications of DFT in diverse areas of chemistry and physics will be discussed.