Special Seminar
Name: Sohang Kundu
Affiliation: Postdoctoral Research Scientist, Columbia University
Title: Quantum and Classical Dynamics of Energy Transfer and Storage Systems: From Photosynthesis to Batteries
Date & Time: Monday, 10th February 2025 at 09:00 a.m.
Venue: Through Microsoft Team
Abstract:
In this talk I will discuss recent work studying the impact of coupled electron-nuclear motion on chemical processes relevant for energy transfer and storage. The talk consists of two sections:
In Section 1, I will explore how electron-vibration couplings influence the dynamics of inter-molecular excitation energy transfer (EET), which has key bearings on our understanding of photosynthetic light harvesting, and on the design of energy-efficient materials. I will mainly recount the development[1,2] and use[3] of real time path integral methods to perform the first all-state, all-mode simulation of EET in the bacterial LH2 complex at room temperature. From this simulation, we discovered that the remarkable (~90%) efficiency and (~1 ps) timescale of EET that have been observed experimentally are enabled by the two-ring arrangement of chromophores and quantum effects associated with nuclear vibrations. I will briefly browse through other consequences of strong electron-vibration couplings – e.g., on the decay of vibronic coherences in cofacial porphyrin dimers[4], and on the scrambling of information[5] by chemical reactions.
Section 2 will focus on chemical reaction dynamics under applied electric fields[6] and in battery systems [7,8]. Aside from the complexities of nuclear motion in the electrolyte solution and at the electrodeelectrolyte interface, the dynamics of such systems are riddled by the external electric field and potentially non-adiabatic electron transfer at the electrodes. I will first describe a recent theory[6] of reaction rates for electric field catalysis in polar solvents. I will then go on to discuss the need to account for explicit dynamics and solvation when studying the formation of the solid-electrolyte interphase (SEI) in lithium-based batteries. Using ab initio molecular dynamics data, we have developed neural network potentials that are allowing us to compute free energies and exact (classical) rates for ethylene carbonate decomposition on the lithium surface[7] at first-principles accuracy. Finally, and if time permits, I will discuss a new approximate method[8] to compute charge-transfer excitations for molecular and metal-molecule interfacial systems using ground state force fields that allow dynamic fluctuations of atomic charges.
I will end the talk with a glimpse of the future work to be undertaken in my group, towards leveraging vibronic dynamics to study materials for energy, catalysis, and quantum information science applications.
References:
[1] S. Kundu and N. Makri, “Modular Path Integral for Finite-Temperature Dynamics of Extended Systems with Intramolecular Vibrations”, Journal of Chemical Physics 153, 044124 (2020)
[2] S. Kundu and N. Makri, “Small Matrix Quantum Classical Path Integral”, Journal of Physical Chemistry Letters, 13, 3492-3498 (2022)
[3] S. Kundu, R. Dani and N. Makri, “Tight Inner Ring Architecture and Quantum Motion of Nuclei Enable Efficient Energy Transfer in Bacterial Light Harvesting”, Science Advances, 8, eadd0023 (2022)
[4] P. P. Roy, S. Kundu, et al, “Synthetic Control of Exciton Dynamics in Bioinspired Cofacial Porphyrin Dimers, Journal of the American Chemical Society, 144, 14, 6298–6310 (2022)
[5] C. Zhang#, S. Kundu#, N. Makri, M. Gruebele, and P. Wolynes, “Quantum Information Scrambling and Chemical Reactions”, Proceedings of the National Academy of Sciences, 121 (15) e2321668121 (2024). #authors contributed equally.
[6] S. Kundu and T.C. Berkelbach, “Reaction Rate Theory for Electric Field Catalysis in Solution”, Journal of the American Chemical Society 146, 38, 26041–26047 (2024)
[7] S. Kundu*, D. Chamaki, H.-Z. Ye, and T.C. Berkelbach*, “Thermal fluctuations and dynamics modulate ethylene carbonate decomposition on lithium”, (to be submitted), (2025). *corresponding author.
[8] S. Kundu*, H.-Z. Ye, and T.C. Berkelbach*, “Diabatic States of Charge Transfer with Constrained Charge Equilibration”, arXiv:2411.04807 (2025), (under revision, at J. Chem. Theory Comput.).