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.
Original language | English |
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Article number | 23 |
Pages (from-to) | 7383-7390 |
Number of pages | 8 |
Journal | Journal of Physical Chemistry Letters |
Volume | 10 |
Early online date | 12 Nov 2019 |
DOIs | |
Publication status | Published - 5 Dec 2019 |
Keywords
- Excitons
- Antennas
- Hamiltonians
- Oscillation
- Chromophores
- Energy
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Alam, S. R. (Manager), Williams, D. A. G. (Manager), Eccleston, P. E. (Manager) & Greene, D. (Manager)
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