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Title: Bayes-Turchin Analysis of Overlapping L-Edges EXAFS Data of Iron

Abstract

Spin polarized and spin averaged extended x-ray absorption fine structure ((M)EXAFS) data were measured at temperatures of 180 K and 296 K in the soft x-ray energy regime of the overlapping L-edges of an iron film grown on V(110). The absorption coefficients were analyzed with the Bayes-Turchin procedure. The analysis yields the correction function to the atomic-like background-absorption coefficient calculated by FEFF8 and reveals components of atomic EXAFS oscillations. The EXAFS Debye-Waller (DW) parameters were determined. Their split into a thermal and a structural contribution was not possible without theoretical input since the two temperatures in this experiment were not sufficiently far apart from each other and the k range of the data was too small. The a priori values of the thermal contribution to the DW parameters were therefore derived from a force-field model with two spring constants. They were adjusted to DW parameters calculated from Born-von Karman force constants which had been obtained from inelastic neutron scattering. Those two spring constants also nicely reproduce the unprojected vibrational density of states deduced from phonon dispersion curves. The MEXAFS oscillations can be described by the rigid-band model and the L2- and L3-EXAFS components. A negative exchange-related energy is obtained bymore » fitting the MEXAFS signal in the extended energy region. This is in contrast to the predictions of the Hedin-Lundquist functional and the Dirac-Hara functional used in the FEFF8 code.« less

Authors:
; ; ;  [1];  [2]
  1. Hahn-Meitner-Institut Berlin, Glienicker Str. 100, D-14109 Berlin (Germany)
  2. Department of Physics, University of Washington, Seattle, Washington 98195.1560 (United States)
Publication Date:
OSTI Identifier:
21054724
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 882; Journal Issue: 1; Conference: XAFS13: 13. international conference on X-ray absorption fine structure, Stanford, CA (United States), 9-14 Jul 2006; Other Information: DOI: 10.1063/1.2644432; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; CORRECTIONS; CRYSTAL STRUCTURE; DEBYE-WALLER FACTOR; DISPERSION RELATIONS; F CODES; FILMS; FINE STRUCTURE; INELASTIC SCATTERING; IRON; NEUTRON DIFFRACTION; PHONONS; SOFT X RADIATION; SPIN; SPIN ORIENTATION; TEMPERATURE DEPENDENCE; VANADIUM; X-RAY SPECTROSCOPY

Citation Formats

Rossner, H. H., Schmitz, D., Imperia, P., Krappe, H. J., and Rehr, J. J. Bayes-Turchin Analysis of Overlapping L-Edges EXAFS Data of Iron. United States: N. p., 2007. Web. doi:10.1063/1.2644432.
Rossner, H. H., Schmitz, D., Imperia, P., Krappe, H. J., & Rehr, J. J. Bayes-Turchin Analysis of Overlapping L-Edges EXAFS Data of Iron. United States. doi:10.1063/1.2644432.
Rossner, H. H., Schmitz, D., Imperia, P., Krappe, H. J., and Rehr, J. J. Fri . "Bayes-Turchin Analysis of Overlapping L-Edges EXAFS Data of Iron". United States. doi:10.1063/1.2644432.
@article{osti_21054724,
title = {Bayes-Turchin Analysis of Overlapping L-Edges EXAFS Data of Iron},
author = {Rossner, H. H. and Schmitz, D. and Imperia, P. and Krappe, H. J. and Rehr, J. J.},
abstractNote = {Spin polarized and spin averaged extended x-ray absorption fine structure ((M)EXAFS) data were measured at temperatures of 180 K and 296 K in the soft x-ray energy regime of the overlapping L-edges of an iron film grown on V(110). The absorption coefficients were analyzed with the Bayes-Turchin procedure. The analysis yields the correction function to the atomic-like background-absorption coefficient calculated by FEFF8 and reveals components of atomic EXAFS oscillations. The EXAFS Debye-Waller (DW) parameters were determined. Their split into a thermal and a structural contribution was not possible without theoretical input since the two temperatures in this experiment were not sufficiently far apart from each other and the k range of the data was too small. The a priori values of the thermal contribution to the DW parameters were therefore derived from a force-field model with two spring constants. They were adjusted to DW parameters calculated from Born-von Karman force constants which had been obtained from inelastic neutron scattering. Those two spring constants also nicely reproduce the unprojected vibrational density of states deduced from phonon dispersion curves. The MEXAFS oscillations can be described by the rigid-band model and the L2- and L3-EXAFS components. A negative exchange-related energy is obtained by fitting the MEXAFS signal in the extended energy region. This is in contrast to the predictions of the Hedin-Lundquist functional and the Dirac-Hara functional used in the FEFF8 code.},
doi = {10.1063/1.2644432},
journal = {AIP Conference Proceedings},
number = 1,
volume = 882,
place = {United States},
year = {Fri Feb 02 00:00:00 EST 2007},
month = {Fri Feb 02 00:00:00 EST 2007}
}