SOLID STATE & STRUCTURAL CHEMISTRY UNIT
INDIAN INSTITUTE OF SCIENCE
BANGALORE – 560 012
Speaker: Ms. Puja Banerjee
Non-Adiabatic Reaction Dynamics
Date & Time: Thursday 18th January, 2018 at 4.00 PM
Venue: SSCU AUDITORIUM
In case of both electronic transition and electron transfer reaction, adiabaticity and non-adiabaticity of potential energy surfaces play a significant role in controlling the rate, even the course of the chemical processes. When the coupling between two states of a system is large, it is said to be adiabatic states, otherwise diabatic (or non-adiabatic). A large number of important chemical and biological processes involve non-adiabatic reactions which makes this field appealing to physical chemists, biologists, material scientists and many more 
Marcus theory provides the foundation for understanding electron transfer reactions which is based on non-adiabatic model. On the other hand, molecular Quantum mechanics, used to study electronic transitions of molecules, is dominated by Born-Oppenheimer (B-O) approximation. When two or more potential energy surfaces come close together, B-O approximation breaks down and non-adiabatic reactions enter into the reaction pathway. A large number of theories, computational methods have been proposed to study such non-adiabatic transitions. Further, recently, an experiment has been carried out, successfully for real time observation of non-adiabatic transition.
In this talk, at first, adiabatic and non-adiabatic transitions will be described, then electron transfer reaction will be discussed with the help of Marcus’s theory. Next, I shall explain non-crossing rule and conical intersection for non-adiabatic electronic transition, why B-O approximation fails to describe non-adiabatic electronic transition and introduce some popular semi-classical methods such as Landau-Zener, Ehrenfest Method and surface hopping technique[4,5,6]. Next, I will conclude my talk with the application of surface hopping method to the photochemistry of DNA nucleobases and the recent experimental observation of non-adiabatic dynamics to achive both spatial and temporal characterization of conical intersections.
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B. Bagchi, Molecular Relaxation in Liquids, Oxford University Press (2012)
R.A. Marcus, “On the Theory of Oxidation-Reduction Reactions Involving Electron Transfer I” J.Chem.Phys.1956, 24, 966.
C. Zener (1932). “Non-Adiabatic Crossing of Energy Levels”. Proceedings of the Royal Society of London A. 137 (6): 696–702
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7. M. Barbatti, “Nonadiabatic dynamics with trajectory surface hopping method.” Wiley Interdisciplinary Reviews: Computational Molecular Science 1.4 (2011): 620-633.
ALL ARE CORDIALLY INVITED TO ATTEND