BibTeX
@MISC{_inyba2c~307-6,
author = {},
title = {in YBa2C~307-6 using DAFS},
year = {}
}
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Abstract
Abstract: The separate complex resonant scattering amplitudes for the two inequivalent Cu sites in Y B ~ ~ C U ~ O ~- ~ have been determined using diffraction anomalous fine structure (DAFS). The combined amplitudes A f (Q, E) for eight specular (00e) reflections were isolated from the measured intensity using the iterative dispersion algorithm of Pickering, et al., modified to accommodate contributions to the imaginary part of the scattering amplitude from the heavy Ba and Y atoms. The individual site response functions ff'(E) were solved by singular value decomposition of the matrix of crystallographic coefficients and applying the inverse matrix to A f (Q, E) at each value of energy. For comparison, a second set of coefficients was obtained by simultaneously fitting the DAFS fine structure functions x(Q, k) using the computer program FEFFIT under a set of constraints. The x(Q, k) were modeled as linear combina-tions of the two Cu site ~ ( k) functions using a kinematic structure factor model with Q as the independent variable and theoretical ~ ( k) from F E F F ~ .
Keyphrases
inequivalent cu singular value decomposition heavy ba inverse matrix imaginary part cu site second set dafs fine structure function iterative dispersion algorithm computer program feffit kinematic structure factor model individual site response function separate complex resonant crystallographic coefficient diffraction anomalous fine structure linear combina-tions
