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The Lorentz-Polarization Factor and Preferred Orientation in Oriented Clay Aggregates

Published online by Cambridge University Press:  02 April 2024

R. C. Reynolds Jr.
R. C. Reynolds Jr.*
Affiliation:
Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire 03755
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Abstract

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A closed-form equation was derived that describes the powder-ring distribution factor as a function of 2θ, soller slit collimation, and σ*, which is defined as the standard deviation of an axially symmetrical Gaussian orientation function. Methods were developed for measuring σ* in the reflection mode by means of a θ/2θ diffractometer. Six experimental arrangements for a sedimentary chlorite showed widely different intensity ratios of the 001/005 reflections and gave a standard deviation of ±5.8% when corrected by the theory. The absolute integrated intensities of the 003 reflection from eleven illite samples provided an eight-fold maximum range which, when corrected, yielded a standard deviation of ±7.7%.

The intensity distributions within each of two X-ray powder diffraction patterns obtained from instruments with different soller-slit configurations could not be directly compared at low diffraction angles unless corrections, based on σ*, were introduced to allow for the differences in axial divergence.

Keywords

ChloriteIlliteIntensity distributionLorentz factorOrientationSoller slitsX-ray powder diffraction
Type
Research Article
Information
Clays and Clay Minerals , Volume 34 , Issue 4 , August 1986 , pp. 359 - 367
Copyright
Copyright © 1986, The Clay Minerals Society

References

Abramowitz, M. and Stegun, A., 1970 Handbook of Mathematical Functions .Google Scholar
Geller, M. and Ng, E. W., 1969 A table of integrals of the exponential integral J. Res. Nat. Bur. Stds.—B. Math. and Math. Sci. 738 191–210.Google Scholar
Hall, P. L., Harrison, R., Hayes, M. H. B. and Tuck, J. J., 1983 Particle orientation distributions and stacking arrangements in size-fractionated montmortillonite measured by neutron and X-ray diffraction J. Chem. Soc. Faraday Trans. 79 1687–1700.CrossRefGoogle Scholar
James, R. W., 1965 The Optical Principles of the Diffraction of X-Rays Ithaca, New York Cornell Univ. Press.Google Scholar
Klug, H. P. and Alexander, L. E., 1974 X-Ray Diffraction Procedures New York Wiley.Google Scholar
Lippmann, F., 1970 Functions describing preferred orientation in flat aggregates of flake-like clay minerals and in other axially symmetric fabrics Contr. Mineral. Petrol. 25 77–94.CrossRefGoogle Scholar
MacEwan, D. M. C., 1956 Fourier transform methods for studying scattering from lamellar systems. I. A direct method for analyzing interstratified mixtures Kolloid 149 96–108.CrossRefGoogle Scholar
Reynolds, R. C., 1976 The Lorentz factor for basal reflections from micaceous minerals in oriented powder aggregates Amer. Mineral. 61 484–491.Google Scholar
Reynolds, R. C., 1980 Quantitative analysis of kaolinite, illite, and mixed-layered illite-smectite by X-ray diffraction methods Prog. Abstracts, 29th Ann. Clay Conf. .Google Scholar
Taylor, R. M. and Norrish, K., 1966 The measurement of orientation distribution and its application to quantitative X-ray diffraction analysis Clay Miner. 6 127–142.CrossRefGoogle Scholar