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Rigid body refinements in GSAS/EXPGUI

Published online by Cambridge University Press:  06 March 2012

Charles H. Lake*
Affiliation:
Indiana University of Pennsylvania, Indiana, Pennsylvania 15705
Brian H. Toby*
Affiliation:
Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439
*
a)Authors to whom correspondence should be addressed. Electronic mail: lake@iup.edu
b)Electronic mail: brian.toby@anl.gov

Abstract

Rigid bodies provide a way to simplify the model used in a crystallographic refinement by removing parameters that describe degrees of freedom that are unlikely to change based on chemical experience. The GSAS software package provides a powerful implementation of rigid bodies that allows for refinement of classes of bond lengths, grouping of bodies to further reduce parameterization and where atomic motion can be described from group displacement parameters (TLS) representation. However, use of rigid bodies in GSAS is complex to learn and time-consuming to perform. This paper describes how the rigid body definition process has been simplified and extended through implementation in the EXPGUI interface to GSAS.

Type
Powder Diffraction Software
Copyright
Copyright © Cambridge University Press 2011

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