151. Effective normal modes identify vibrational motions which maximally promote vibronic mixing in excitonically coupled aggregates
- Author
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Vivek Tiwari, Sanjoy Patra, and Amitav Sahu
- Subjects
Physics ,Toy model ,010304 chemical physics ,General Physics and Astronomy ,010402 general chemistry ,01 natural sciences ,Molecular physics ,Resonance (particle physics) ,0104 chemical sciences ,Vibration ,symbols.namesake ,Vibronic coupling ,Normal mode ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,symbols ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,Hamiltonian (quantum mechanics) ,Mixing (physics) ,Curse of dimensionality - 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.
- Published
- 2021