Abstract's Details

Time-Dependent Density Functional Calculations of XAS Pre-edges: Applications to Ligand and Metal K-edges
Abstract ID	W:XANES-05
Presenter	Serena DeBeer George
Presentation Type	XANES Workshop
Full Author List	SSR, SLAC, Stanford University (1)
Affiliations	(1) Serena DeBeer George
Category	Bio/Life Sciences
Abstract	Recent results using time-dependent density functional theory (TD-DFT) to simulate ligand and metal K- pre-edge features will be presented. All calculations were performed using the electronic structure package ORCA, developed by F. Neese. The methodology has been calibrated using a series of metal tetrachlorides, as well-defined reference complexes. The influence of the chosen density functional, relativistics, basis set, and solvation on the calculated Cl K-edge spectra has been systematically investigated. These methods have also been extended to a series of transition metal dithiolenes and most recently have been applied to the Mn K-edges of model complexes relevant to the oxygen-evolving complex in photosystem II. For these complexes, polarized XAS spectra of Mn(V)-oxo and Mn(V)-nitrido model complexes were obtained. Single crystals of the Mn(V)-nitrido and Mn(V)-oxo compounds were aligned along selected molecular vectors with respect to the X-ray polarization vector using X-ray diffraction. The polarized data allow for a clear and detailed correlation of the experimental data to the calculations. The relevance of these results to the understanding of other high-valent metal-oxo species and to the mechanism of photosynthetic water oxidation will be discussed.
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Funding Acknowledgement