Argonne National Laboratory

Upcoming Events

First-principles Interpretations of Near-edge X-ray Absorption and Inelastic X-ray Scattering at K-edges in Condensed Phases: the Role of Static and Dynamical and Symmetry-breaking

February 4, 2013 11:00AM to 12:00PM
David Prendergast, LBNL
Building 200, Room J183
CSE Special Seminar
The increasing application of synchrotron light sources to characterization of complex materials under working conditions creates more demand for accurate, first-principles approaches to interpret spectroscopy. In this talk, we address the use of constrained excited-state density functional theory (DFT) in approximating 1s core-excited states of atoms in condensed phase materials and the subsequent simulation of X-ray absorption spectra with predictive accuracy. Our approach describes the core-excited state with explicit inclusion of both the excited electron and Core-Hole (XCH).

We highlight specific details that enable us to accurately reproduce absorption onsets with 0.1-0.2 eV accuracy and to include experimental sampling of dynamical degrees of freedom via first-principles molecular dynamics. Applications will be presented to materials of relevance to electrical energy storage and gas separations. Particular emphasis will be placed on developing a keen understanding of new spectral features that arise purely from static or dynamical symmetry-breaking in the neighborhood of the core-excited atom and how this knowledge can be exploited to design future in situ experiments on materials in operando.