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Theoretical EXAFS studies of a model of the oxygen‐evolving complex of photosystem II obtained with the quantum cluster approach
Author(s) -
Li Xichen,
Sproviero Eduardo M.,
Ryde Ulf,
Batista Victor S.,
Chen Guangju
Publication year - 2012
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.24143
Subject(s) - extended x ray absorption fine structure , cluster (spacecraft) , photosystem ii , chemistry , oxygen evolving complex , absorption (acoustics) , quantum , chemical physics , atomic physics , absorption spectroscopy , physics , photosynthesis , optics , quantum mechanics , computer science , biochemistry , programming language
The oxygen‐evolving complex (OEC) of photosystem II is the only natural system that can form O 2 from water and sunlight and it consists of a Mn 4 Ca cluster. In a series of publications, Siegbahn has developed a model of the OEC with the quantum mechanical (QM) cluster approach that is compatible with available crystal structures, able to form O 2 with a reasonable energetic barrier, and has a significantly lower energy than alternative models. In this investigation, we present a method to restrain a QM geometry optimization toward experimental polarized extended X‐ray absorption fine structure (EXAFS) data. With this method, we show that the cluster model is compatible with the EXAFS data and we obtain a refined cluster model that is an optimum compromise between QM and polarized EXAFS data. © 2012 Wiley Periodicals, Inc.