Effective normal modes identify vibrational motions which maximally promote vibronic mixing in excitonically coupled aggregates

Patra, S and Sahu, A and Tiwari, V (2021) Effective normal modes identify vibrational motions which maximally promote vibronic mixing in excitonically coupled aggregates. In: Journal of Chemical Physics, 154 (11).

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Abstract

Controlling energy transfer through vibronic resonance is an interesting possibility. Exact treatment of non-adiabatic vibronic coupling is necessary to fully capture its role in driving energy transfer. However, the exact treatment of vibrations in extended systems is expensive, sometimes requiring oversimplifying approximations to reduce vibrational dimensionality, and do not provide physical insights into which specific vibrational motions promote energy transfer. In this communication, we derive effective normal modes for understanding vibronically enhanced energy transfer in excitonically coupled aggregates. We show that the dynamics of the overall high-dimensional vibronic Hamiltonian can be better understood through one-dimensional Hamiltonians separable along these effective modes. We demonstrate this approach on a trimer toy model to analyze the role of an intermediate "trap"site in mediating energy transfer between electronically uncoupled sites. Bringing uncoupled sites into vibronic resonance converts the "trap"into a "shuttle"for energy transfer. By deconvolving the dynamics along the aggregate normal modes, our approach identifies the specific vibrational motions, which maximally promote energy transfer, against spectator modes, which do not participate in vibronic mixing. © 2021 Author(s).

Item Type:	Journal Article
Publication:	Journal of Chemical Physics
Publisher:	American Institute of Physics Inc.
Additional Information:	The copyright for this article belongs to American Institute of Physics Inc.
Keywords:	Aggregates; Hamiltonians; Mixing, Extended systems; High-dimensional; Non-adiabatic; Normal modes; Toy models; Vibrational motions; Vibronic coupling; Vibronic mixing, Energy transfer
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	20 Apr 2021 10:30
Last Modified:	20 Apr 2021 10:30
URI:	http://eprints.iisc.ac.in/id/eprint/68632

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