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Diffraction line profile from a disperse system: A simple alternative to Voigtian profiles

Published online by Cambridge University Press:  01 March 2012

P. Scardi ,
M. Leoni  and
J. Faber
P. Scardi
Affiliation:
Department of Materials Engineering and Industrial Technologies, University of Trento, 38050 via Mesiano 77, Trento, Italy
M. Leoni
Affiliation:
Department of Materials Engineering and Industrial Technologies, University of Trento, 38050 via Mesiano 77, Trento, Italy
J. Faber
Affiliation:
International Centre for Diffraction Data, 12 Campus Boulevard, Newtown Square, Pennsylvania 19073-3273
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Abstract

A general expression is proposed for the peak profile produced by a system of simple-shape crystalline domains (sphere, cube, tetrahedron, octahedron) whose size is dispersed according to a gamma distribution. The analytical expression obtained is particularly suited to “on the fly” pattern simulation or profile fitting for nanocrystalline materials. An advantage of using the proposed profile expression is that it always corresponds to a physically meaningful, though a priori fixed, size distribution, whereas the traditionally employed Voigtian profiles can produce unphysical negative size distributions for certain combinations of profile parameters. The peak profile depends on the distribution mean and variance instead of the more common empirical parameters of peak width and shape.

Keywords

profile fittingline profile analysisdomain size distributionnanocrystalline materialspowder diffraction

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Type
Technical Articles
Information
Powder Diffraction , Volume 21 , Issue 4 , December 2006 , pp. 270 - 277
Copyright
Copyright © Cambridge University Press 2006

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