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Published on: August 28, 2018
Population and coherence dynamics in light harvesting complex II (LH2)
Shu-Hao Yeh1, Jing Zhu, Sabre Kais
1Department of Chemistry and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
The Journal of Chemical Physics
|September 4, 2012
Summary
Photosynthetic light harvesting complex 2 (LH2) B850 ring exhibits excitation population and coherence oscillations. Environmental and temperature factors influence exciton dynamics, revealing long-lived coherence in biological systems.
Area of Science:
- Photosynthetic light harvesting complex 2 (LH2) B850 ring
- Purple bacteria (Rhodopseudomonas acidophila)
Background:
- Investigates electronic excitation population and coherence dynamics in LH2 B850 chromophores.
- Compares dynamics to the well-studied Fenna-Matthews-Olson (FMO) protein.
Purpose of the Study:
- To theoretically study excitation population and coherence dynamics in LH2 B850.
- To analyze the influence of physiological and cryogenic temperatures on these dynamics.
- To understand exciton wave packet propagation and coherence in biological environments.
Main Methods:
- Employs a scaled hierarchical equation of motion approach.
- Theoretical study at both physiological and cryogenic temperatures.
- Analysis of excitation population and coherence oscillations.
Main Results:
- Observed oscillations in excitation population and coherence in LH2 B850, similar to FMO protein.
- LH2 B850 oscillation time (300 fs) is shorter than FMO protein (650 fs) at cryogenic temperatures.
- Environment and high temperature enhance exciton wave packet propagation but shorten coherence time and suppress oscillation amplitude.
Conclusions:
- A long-lived coherence between chromophore electronic excited states can exist in noisy biological environments.
- Environmental factors and temperature significantly impact exciton dynamics in LH2.
- The study provides insights into the mechanisms of light harvesting in photosynthetic systems.
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