Colloquium – Lavanya Ramaniah – First Principles Simulations of Condensed Phase Systems: From Si to DNA

Speaker: Dr. Lavanya Ramaniah (University of Mumbai)

Title: First Principles Simulations of Condensed Phase Systems: From Si to DNA

Abstract:

The realistic understanding and description of physical and chemical systems, and consequent prediction of their behavior under a wide variety of conditions, is the dream of scientists. This dream has come closer to realization in recent years, thanks at least in part to first-principles quantum-mechanical simulations, which enable the scientist to obtain an Accurate picture of what happens, structurally and dynamically, even at the atomic level. The earliest first-principles calculations several decades ago were restricted to studies on relatively simple systems such as elemental semiconductors. Since then, advances in theory, algorithms and computing power have made possible the study of increasingly complex systems of physical, chemical, and even biological importance, on a scale unthinkable until just a few years ago. In this talk, we shall discuss some of our work on systems as diverse as clusters, liquids and solids under pressure within the context of density functional theory (DFT), widely used in these calculations. Thus, novel energy materials for photovoltaics (semiconductor, perovskite quantum dots in configurations such as core/shell, push/pull), and hydrogen storage (metal-doped graphene, graphyne) will be described. Pressure induced polymeri[1]zation of Acrylamide is found to be facilitated by the anisotropic response of the hydrogen bonding network, while hybrid perovskites may be treated as host/guest systems for understanding the transitions across the phases. The study of alkali metal ion solvation in bulk water yields insight into this important bio-chemical process. Ad atom motion on a curved surface, investigated through the study of a single alkali metal atom on a fullerene molecule, shows several regimes of behavior. The confirmative and predictive powers of ab initio studies will be further highlighted using a few examples from the literature of interest to other fields as well.