Background modelling in Rietveld analysis [electronic resource]
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| Online Access: |
Online Access |
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| Format: | Government Document Electronic eBook |
| Language: | English |
| Published: |
Washington, D.C. : Oak Ridge, Tenn. :
United States. Dept. of Defense ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy,
1989.
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| Subjects: |
| Abstract: | The Rietveld method is a complete profile fitting technique, which requires modelling the total scattering from crystalline samples. Many diffraction experiments involve the analysis of scattering patterns containing additional noncrystalline scattering components; these components are broad oscillations superimposed on the sharp Bragg pattern. Conventional background functions cannot be used for the noncrystalline scattering; but treating the additional scattering as though it were from an amorphous material can provide additional structural information. This is demonstrated using AlPO₄-5, an aluminophosphate framework molecular sieve. The correlation function for the amorphous component has peaks close to interatomic distances also characteristic of the crystal. The cose agreement suggests that the amorphous component, although lacking long-range periodicity, has a similar atomic arrangement to the crystal. A calibration experiment is performed using a 50-50 wt% quartz-amorphous silica mixture; the crystal structural parameters obtained from Fourier-filtered data are compared with neutron powder diffraction refinement of quartz and single-crystal x-ray results. All refined parameters agree within 3-4 σ. 2 tables, 5 refs, 6 figs. (DLC) |
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| Item Description: | Published through the Information Bridge: DOE Scientific and Technical Information. 01/01/1989. "anl/cp-76818" " conf-8906324--2" "DE92018791" International workshop on the Rietveld method, Petten (Netherlands), 13-15 Jun 1989. Richardson, J.W. Jr. |
| Physical Description: | Pages: (13 p) : digital, PDF file. |