Coherent Exciton Dynamics in the Presence of Underdamped Vibrations
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Cao_Coherent exciton.pdf
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Author(s)
Wang, Chen
Fleming, Graham R.
Dijkstra, Arend Gerrit
Cao, Jianshu
Date Issued
January 2015
Journal
The Journal of Physical Chemistry Letters
Publisher
American Chemical Society (ACS)
Citation
Dijkstra, Arend G. et al. “Coherent Exciton Dynamics in the Presence of Underdamped Vibrations.” The Journal of Physical Chemistry Letters 6.4 (2015): 627–632. © 2015 American Chemical Society
Version
Original manuscript
Abstract
Recent ultrafast optical experiments show that excitons in large biological light-harvesting complexes are coupled to molecular vibration modes. These high-frequency vibrations will not only affect the optical response, but also drive the exciton transport. Here, using a model dimer system, the frequency of the underdamped vibration is shown to have a strong effect on the exciton dynamics such that quantum coherent oscillations in the system can be present even in the case of strong noise. Two mechanisms are identified to be responsible for the enhanced transport efficiency: critical damping due to the tunable effective strength of the coupling to the bath, and resonance coupling where the vibrational frequency coincides with the energy gap in the system. The interplay of these two mechanisms determines parameters responsible for the most efficient transport, and these optimal control parameters are comparable to those in realistic light-harvesting complexes. Interestingly, oscillations in the excitonic coherence at resonance are suppressed in comparison to the case of an off-resonant vibration.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1021/jz502701u
