Structure and Efficiency in Bacterial Photosynthetic Light Harvesting

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

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

2 Citations (Scopus)

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 languageEnglish
Article number23
Pages (from-to)7383-7390
Number of pages8
JournalJournal of Physical Chemistry Letters
Volume10
Early online date12 Nov 2019
DOIs
Publication statusPublished - 5 Dec 2019

Keywords

  • Excitons
  • Antennas
  • Hamiltonians
  • Oscillation
  • Chromophores
  • Energy

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