Issue 45, 2019

Electronic coherence lifetimes of the Fenna–Matthews–Olson complex and light harvesting complex II

Abstract

The study of coherence between excitonic states in naturally occurring photosynthetic systems offers tantalizing prospects of uncovering mechanisms of efficient energy transport. However, experimental evidence of functionally relevant coherences in wild-type proteins has been tentative, leading to uncertainty in their importance at physiological conditions. Here, we extract the electronic coherence lifetime and frequency using a signal subtraction procedure in two model pigment-protein-complexes (PPCs), light harvesting complex II (LH2) and the Fenna–Matthews–Olson complex (FMO), and find that the coherence lifetimes occur at the same timescale (<100 fs) as energy transport between states at the energy level difference equal to the coherence energy. The pigment monomer bacteriochlorophyll a (BChla) shows no electronic coherences, supporting our methodology of removing long-lived vibrational coherences that have obfuscated previous assignments. This correlation of timescales and energy between coherences and energy transport reestablishes the time and energy scales that quantum processes may play a role in energy transport.

Graphical abstract: Electronic coherence lifetimes of the Fenna–Matthews–Olson complex and light harvesting complex II

Supplementary files

Article information

Article type
Edge Article
Submitted
15 jul 2019
Accepted
08 sep 2019
First published
19 sep 2019
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2019,10, 10503-10509

Electronic coherence lifetimes of the Fenna–Matthews–Olson complex and light harvesting complex II

S. Irgen-Gioro, K. Gururangan, R. G. Saer, R. E. Blankenship and E. Harel, Chem. Sci., 2019, 10, 10503 DOI: 10.1039/C9SC03501J

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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