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          Institute: MPI für bioanorganische Chemie     Collection: MPI für bioanorganische Chemie     Display Documents

ID: 712718.0, MPI für bioanorganische Chemie / MPI für bioanorganische Chemie
How Accurately Can Extended X-ray Absorption Spectra Be Predicted from First Principles? Implications for Modeling the Oxygen-Evolving Complex in Photosystem II
Authors:Beckwith, Martha A.; Ames, William M.; Vila, Fernando D.; Krewald, Vera Lucia; Pantazis, Dimitrios A.; Mantel, Claire; Pecaut, Jacques; Gennari, Marcell; Duboc, Carole; Collomb, Marie-Noelle; Yano, Junko; Rehr, John J.; Neese, Frank; DeBeer, Serena
Date of Publication (YYYY-MM-DD):2015
Title of Journal:Journal of the American Chemical Society
Journal Abbrev.:J. Am. Chem. Soc.
Issue / Number:40
Start Page:12815
End Page:12834
Review Status:Internal review
Audience:Experts Only
Abstract / Description:First principle calculations of extended X-ray absorption fine structure (EXAFS) data have seen widespread use in bioinorganic chemistry, perhaps most notably for modeling the Mn4Ca site in the oxygen evolving complex (OEC) of photosystem II (PSII). The logic implied by the calculations rests on the assumption that it is possible to a priori predict an accurate EXAFS spectrum provided that the underlying geometric structure is correct. The present study investigates the extent to which this is possible using state of the art EXAFS theory. The FEFF program is used to evaluate the ability of a multiple scattering-based approach to directly calculate the EXAFS spectrum of crystallographically defined model complexes. The results of these parameter free predictions are compared with the more traditional approach of fitting FEFF calculated spectra to experimental data. A series of seven crystallographically characterized Mn monomers and dimers is used as a test set. The largest deviations between the FEFF calculated EXAFS spectra and the experimental EXAFS spectra arise from the amplitudes. The amplitude errors result from a combination of errors in calculated S-0(2) and Debye-Waller values as well as uncertainties in background subtraction. Additional errors may be attributed to structural parameters, particularly in cases where reliable high-resolution crystal structures are not available. Based on these investigations, the strengths and weaknesses of using first-principle EXAFS calculations as a predictive tool are discussed. We demonstrate that a range of DFT optimized structures of the OEC may all be considered consistent with experimental EXAFS data and that caution must be exercised when using EXAFS data to obtain topological arrangements of complex clusters.
Comment of the Author/Creator:Date: 2015, OCT 14 2015
External Publication Status:published
Document Type:Article
Version Comment:Automatic journal name synchronization
Communicated by:N. N.
Affiliations:MPI für bioanorganische Chemie
External Affiliations:[Vila,F.D.; Rehr,J.J.] Univ Washington, Dept Phys, Seattle, WA 98195 USA.
[Mantel,C.; Gennari,M.; Duboc,C.; Collomb,M.-N.] Univ Grenoble 1, CNRS, Dept Chim Mol, F-38000 Grenoble, France.
[Pecaut,J.] CEA, CNRS, Serv Chim Inorgan & Biol,UJF,INAC,FRE3200, Lab Reconnaissance Ionique & Chim Coordinat,UMR E, F-38054 Grenoble 9, France.
[Yano,J.] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Phys Biosci Div, Berkeley, CA 94720 USA.
Identifiers:ISI:000363002900021 [ID No:1]
ISSN:0002-7863 [ID No:2]
DOI:10.1021/jacs.5b00783 [ID No:3]
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