Towards quantification of vibronic coupling in photosynthetic antenna complexes
Abstract
Photosynthetic antenna complexes harvest sunlight and efficiently transport energy to the reaction center where charge separation powers biochemical energy storage. The discovery of existence of long lived quantum coherence during energy transfer has sparked the discussion on the role of quantum coherence on the energy transfer efficiency. Early works assigned observed coherences to electronic states, and theoretical studies showed that electronic coherences could affect energy transfer efficiency—by either enhancing or suppressing transfer. However, the nature of coherences has been fiercely debated as coherences only report the energy gap between the states that generate coherence signals. Recent works have suggested that either the coherences observed in photosynthetic antenna complexes arise from vibrational wave packets on the ground state or, alternatively, coherences arise from mixed electronic and vibrational states. Understanding origin of coherences is important for designing molecules for efficient light harvesting. Here, we give a direct experimental observation from a mutant of LH2, which does not have B800 chromophores, to distinguish between electronic, vibrational, and vibronic coherence. We also present a minimal theoretical model to characterize the coherences both in the two limiting cases of purely vibrational and purely electronic coherence as well as in the intermediate, vibronic regime.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 21, 2015
- Source ID
- 10.1063/1.4921324
Entities
People
- A. T. Gardiner
- C. Wang
- Gregory S. Engel
- M. Westberg
- P. D. Dahlberg
- R. J. Cogdell
- T. Gellen
- V. P. Singh
Organizations
- Air Force Office of Scientific Research
- Biotechnology and Biological Sciences Research Council
- Defense Advanced Research Projects Agency
- Fulbright Foundation
- National Institutes of Health
- National Science Foundation
- University of Chicago
- University of Glasgow