Intramolecular Vibrational Energy Redistribution: Analogies, Insights, and Challenges

The phenomenon of intramolecular vibrational energy redistribution (IVR) is at the heart of chemical reactivity. The inception of this subject goes back to the early beginnings of the field of chemical physics itself and has been the focus of several experimental and theoretical enquiries. However, despite half a century’s worth of studies, researchers are still actively engaged in deciphering the mechanisms of molecular energy flow. Indeed, precise and elegant experiments are starting to upturn and challenge our theoretical understanding of the subject. Questions are being asked about the validity of venerable theories like the transition state theory and the presumed statistical nature of chemical reactions. Even the cherished notions of minimum energy paths, intrinsic reaction paths and golden rule principle need to be critically analyzed in light of the recent advances. Interestingly, and perhaps ironically, the need for such a critical reassessment has come about due to the increasing interest in understanding and controlling chemical phenomena at the single and few (clusters) molecules level.

Several issues still await clear resolution and fascinating phenomena that are emerging from the various experiments raise new challenges for theorists. The paradigmatic, and much awaited, shift from understanding the reaction mechanism to active manipulation of the reaction pathways will be greatly aided by a concerted effort to characterize the nature of energy flow in molecules. This talk gives a general introduction to the phenomenon of IVR and its role in chemical reaction dynamics and control. In particular, a large part of the talk has to do with several interesting analogies/connections between IVR and other, apparently unrelated, topics like Anderson localization, trapped Bose-Einstein condensates, and quantum chaos. Finally, a glimpse of the modest progress made by us towards understanding and answering a few of the many challenges in the field will be given.
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About the Speaker : Prof. Srihari Keshavamurthy obtained his Ph.D.from the Univ. of California,Berkeley and was a post-doc in Cornell University. He joined IIT Kanpur in 1997. His research areas comprise of understanding why and how chemical reactions occur from classical, semi-classical, and quantum perspectives,classical-quantum correspondence in non-integrable systems and phase transport/topology, and areas with overlaps in Physics and Mathematical Physics. This colloquium will be part of the DCS annual meeting.