Structure and Efficiency in Bacterial Photosynthetic Light Harvesting

Bourne Worster, Susannah; Stross, Clement; Vaughan, Felix M. W. C.; Linden, Noah; Manby, Frederick R.

Abstract

Photosynthetic organisms use networks of chromophores to absorb and deliver solar energy to reaction centers. We present a detailed model of the light-harvesting complexes in purple bacteria, including explicit interaction with sunlight, radiative and nonradiative energy loss, and dephasing and thermalizing effects of coupling to a vibrational bath. We capture the effect of slow vibrations by introducing time-dependent disorder. Our model describes the experimentally observed high efficiency of light harvesting, despite the absence of long-range quantum coherence. The one-exciton part of the quantum state fluctuates continuously but remains highly mixed at all times. These results suggest a relatively minor role for structure in determining efficiency. We build hypothetical models with randomly arranged chromophores but still observe high efficiency when nearest-neighbor distances are comparable to those in nature. This helps explain the high transport efficiency in organisms with widely differing antenna structures and suggests new design criteria for artificial light-harvesting devices.

Citation

Bourne Worster, S., Stross, C., Vaughan, F. M. W. C., Linden, N., & Manby, F. R. (2019). Structure and Efficiency in Bacterial Photosynthetic Light Harvesting. Journal of Physical Chemistry Letters, 10(23), 7383-7390. https://doi.org/10.1021/acs.jpclett.9b02625

• Journal Article Type: Letter
• Acceptance Date: Nov 12, 2019
• Online Publication Date: Nov 12, 2019
• Publication Date: Dec 5, 2019
• Deposit Date: Jan 27, 2025
• Journal: The Journal of Physical Chemistry Letters
• Electronic ISSN: 1948-7185
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Issue: 23
• Pages: 7383-7390
• DOI: https://doi.org/10.1021/acs.jpclett.9b02625
• Public URL: https://durham-repository.worktribe.com/output/3353458