Abstract
The mechanism of electron transfer (ET) from reduced pheophytin (Pheo−) to the primary stable photosynthetic acceptor, a quinone (Q) molecule, is addressed by using high-level ab initio computations and realistic molecular models. The results reveal that the ET process involving the (Pheo−+Q) and (Pheo+Q−) oxidation states can be seen essentially as an ultrafast radiationless transition between the two hypersurfaces taking place via conical intersections (CIs) and is favoured when the topology of the interacting moieties makes possible some overlap between the lowest occupied molecular orbitals (LUMO) of the two systems. Thus, it is anticipated that large scale motions, which are difficult to monitor experimentally, may actually occur in the photosynthetic reaction centers of bacteria, algae, and higher plants, to fulfil the observed ultrafast ET processes.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Almöf J, Fischer TH, Gassman PG, Ghosh A, Häser M (1993) Electron correlation in tetrapyrroles: Ab initio calculations on porphyrin and the tautomers of chlorin J Phys Chem 97:10964-10970.
Andersson K, Malmqvist PÅ, Roos BO (1992) Second-order perturbation theory with a complete active space self-consistent field reference function. J Chem Phys 96:1218-1226.
Andersson K et al., MOLCAS, version 6.0 (2004) Department of Theoretical Chemistry, Chemical Centre, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden.
Dekker JP, van Grondelle R (2000) Primary charge separa-tion in photosystem II. Photosynth Res 63:195-208.
Domcke W, Yarkony DR, Köppel H (eds) (2004) Conical intersections: Electronic structure, dynamics and spec- troscopy. World Scientific, Singapore.
Fernández E, Blancafort L, Olivucci M, Robb MA (2000) Intramolecular electron transfer: Independent (ground state) adiabatic (chemical) and nonadiabatic reaction pathways in bis(hydrazine) radical cations. J Am Chem Soc 122:7528-7533.
Forsberg J, Malmqvist PÅ (1997) Multiconfiguration per-turbation theory with imaginary level shift. Chem Phys Lett 274:196-204.
Frisch MJ et al., Gaussian 98 (Revision A.6) (1998) Gaussian Inc., Pittsburg.
Frutos LM, Castaño O, Merchán M (2003) Theoretical determination of the singletsinglet and singlettriplet electronic spectra, lowest ionization potentials, and electron affinity of cyclooctatetraene. J Phys Chem A 107:5472-5478.
Gouterman M, Wagnière G, Snyder LC (1963) Spectra of porphyrins - Part II. Four orbital model. J Mol Spectrosc 11:108-127.
Hasegawa J, Ozeki Y, Ohkawa K, Hada M, Nakatsuji H (1998) Theoretical study of the excited states of chlorin, bacteriochlorin, pheophytin a, and chloro-phyll a by the SAC/SAC-CI method. J Phys Chem B 102:1320-1326.
Merchán M, Serrano-Andrés L (2005). In: Olivucci M (ed) Computational Photochemistry. Elsevier, Amsterdam, The Netherlands.
Olaso-González G, Merchán M, Serrano-Andrés L (2006) Ultrafast electron transfer in photosynthesis: Reduced pheophytin and quinone interaction mediated by coni-cal intersections. J Phys Chem B 110:24734-24739.
Olivucci M. (ed) (2005) Computational photochemistry. In: Theoretical and Computational Chemistry, Vol. 16. Elsevier, Amsterdam, The Netherlands.
Pou-Amérigo R, Merchán M, Ortí E (1999) Theoretical study of the electronic spectrum of p-benzoquinone. J Chem Phys 110:9536-9546.
Rubio M, Roos BO, Serrano-Andrés L, Merchán M (1999) Theoretical tudy of the electronic spectrum of magne-sium-porphyrin. J Chem Phys 110:7202-7209.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2008 Springer Science + Business Media, B.V.
About this paper
Cite this paper
Olaso-González, G., Merchán, M., Serrano-Andrés, L. (2008). Toward an Understanding of Ultrafast Electron Transfer in Photosynthesis. In: Allen, J.F., Gantt, E., Golbeck, J.H., Osmond, B. (eds) Photosynthesis. Energy from the Sun. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-6709-9_146
Download citation
DOI: https://doi.org/10.1007/978-1-4020-6709-9_146
Publisher Name: Springer, Dordrecht
Print ISBN: 978-1-4020-6707-5
Online ISBN: 978-1-4020-6709-9
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)