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Bacterial photosynthesis begins with quantum-mechanical coherence
1Institute of Materials Science, University of Tsukuba, Japan. sumi@ims.tsukuba.ac.jp
Chemical Record (New York, N.Y.)
|April 5, 2002
Summary
Photosynthetic bacteria utilize quantum coherence in pigment aggregates for efficient excitation-energy transfer (EET). A new formula accounts for aggregate size effects, enabling rapid EET even between optically forbidden states.
Area of Science:
- Photosynthesis research
- Quantum biology
- Biophysics
Background:
- Pigment aggregates in photosynthetic bacteria exhibit quantum-mechanical coherence.
- Excitons within these aggregates are crucial for light harvesting and excitation-energy transfer (EET).
- Traditional Förster's formula for EET is insufficient for optically forbidden states.
Purpose of the Study:
- To explain rapid EET to/from optically forbidden exciton states in photosynthetic bacteria.
- To develop a generalized formula for EET rate constants considering aggregate size effects.
- To reconcile quantum coherence effects with efficient energy transfer.
Main Methods:
- Theoretical analysis of exciton dynamics in pigment aggregates.
- Development of a new EET rate constant formula.
- Consideration of aggregate physical size and transition dipole effects.
Main Results:
- Exciton coherence can hinder EET according to traditional theories.
- The physical size of pigment aggregates circumvents coherence limitations.
- A new formula accurately describes rapid EET, including to/from forbidden states, by incorporating aggregate size effects.
Conclusions:
- Bacterial antenna systems efficiently manage EET by leveraging aggregate size effects.
- The developed formula provides a more comprehensive understanding of EET in biological systems.
- This work advances the study of quantum phenomena in biological energy transfer.