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Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1992 Dec 1;89(23):11632–11636. doi: 10.1073/pnas.89.23.11632

Subpicosecond equilibration of excitation energy in isolated photosystem II reaction centers.

J R Durrant 1, G Hastings 1, D M Joseph 1, J Barber 1, G Porter 1, D R Klug 1
PMCID: PMC50607  PMID: 1454856

Abstract

Photosystem II reaction centers have been studied by femtosecond transient absorption spectroscopy. We demonstrate that it is possible to achieve good photoselectivity between the primary electron donor P680 and the majority of the accessory chlorins. Energy transfer can be observed in both directions between P680 and these accessory chlorins depending on which is initially excited. After excitation of either P680 or the other chlorins, the excitation energy is observed to equilibrate between the majority of these pigments at a rate of 100 +/- 50 fs-1. This energy-transfer equilibration takes place before any electron-transfer reactions and must therefore be taken into account in studies of primary electron-transfer reactions in photosystem II. We also show further evidence that the initially excited P680 excited singlet state is delocalized over at least two chlorins and that this delocalization lasts for at least 200 fs.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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