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|Title:||Excitation transfer and trapping kinetics in plant photosystem I probed by two-dimensional electronic spectroscopy||Authors:||Akhtar, Parveen
Lambrev, Petar H.
|Keywords:||Excitation Energy Transfer
|Issue Date:||2017||Source:||Akhtar, P., Zhang, C., Liu, Z., Tan, H.-S., & Lambrev, P. H. (2018). Excitation transfer and trapping kinetics in plant photosystem I probed by two-dimensional electronic spectroscopy. Photosynthesis Research, 135(1-3), 239-250.||Series/Report no.:||Photosynthesis Research||Abstract:||Photosystem I is a robust and highly efficient biological solar engine. Its capacity to utilize virtually every absorbed photon’s energy in a photochemical reaction generates great interest in the kinetics and mechanisms of excitation energy transfer and charge separation. In this work, we have employed room-temperature coherent two-dimensional electronic spectroscopy and time-resolved fluorescence spectroscopy to follow exciton equilibration and excitation trapping in intact Photosystem I complexes as well as core complexes isolated from Pisum sativum. We performed two-dimensional electronic spectroscopy measurements with low excitation pulse energies to record excited-state kinetics free from singlet–singlet annihilation. Global lifetime analysis resolved energy transfer and trapping lifetimes closely matches the time-correlated single-photon counting data. Exciton energy equilibration in the core antenna occurred on a timescale of 0.5 ps. We further observed spectral equilibration component in the core complex with a 3–4 ps lifetime between the bulk Chl states and a state absorbing at 700 nm. Trapping in the core complex occurred with a 20 ps lifetime, which in the supercomplex split into two lifetimes, 16 ps and 67–75 ps. The experimental data could be modelled with two alternative models resulting in equally good fits—a transfer-to-trap-limited model and a trap-limited model. However, the former model is only possible if the 3–4 ps component is ascribed to equilibration with a “red” core antenna pool absorbing at 700 nm. Conversely, if these low-energy states are identified with the P700 reaction centre, the transfer-to-trap-model is ruled out in favour of a trap-limited model.||URI:||https://hdl.handle.net/10356/89330
|ISSN:||0166-8595||DOI:||10.1007/s11120-017-0427-2||Rights:||© 2017 Springer Science+Business Media B.V. This is the author created version of a work that has been peer reviewed and accepted for publication by Photosynthesis Research, Springer Science+Business Media B.V. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1007/s11120-017-0427-2].||Fulltext Permission:||open||Fulltext Availability:||With Fulltext|
|Appears in Collections:||SPMS Journal Articles|
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