Application du lissage des raies de diffraction des rayons X à la séparation du doubletKα1Kα2

Mignot, Jean‐François; Rondot, D.

doi:10.1107/s0021889876011928

Cited by 14 publications

(7 citation statements)

References 9 publications

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“…To a first approximation, the description of the spectral dispersion can be given by the proper combination of two Cauchy-like functions (Hoyt, 1932;Ekstein & Siegel, 1949). For the Ka doublet, rather than adopting an analytical representation including asymmetry parameters (Ladell, Parrish & Taylor, 1959;Ladell, Zagofsky & Pearlman, 1975), or the modulated Lorentzian function proposed by Mignot & Rondot (1976), we maintain for each of the Ka lines the simple approximate equation given by AS:…”

Section: The Methodsmentioning

confidence: 99%

Scan-truncation corrections in single-crystal diffractometry: an empirical method

Destro¹,

Marsh²

1987

Acta Cryst Sect A

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A satisfactory model for experimental 0-20 scan profiles of single-crystal diffraction intensities can be obtained by convoluting the spectral dispersion with the intrinsic profile and then with a third angle-dependent function which we call an 'aberration function'. The first of these functions is calculated on the basis of theoretical components, while the other two are obtained from experimental measurements. The process includes accurate measurement of the inherent background, smoothing the profiles by Fourier analysis and synthesis, deconvolution and least-squares treatments. The method has been applied to data collected at 23 K, up to 20Mo = 100 °, from a spherical crystal of L-alanine. Model profiles are in excellent agreement with the experimental ones, and were used to evaluate truncation losses for several scan ranges. For the instrumental configuration of the diffractometer used in this investigation, scan-truncation losses are far larger than predicted by previous studies. AbstractGeneral equations are presented for diffuse scattering due to static substitutional and orientational disorder in molecular crystals. Scattering due to displacements, both static and dynamic, and molecular librations is treated separately. Examples of a pair of isostructural isomers of dibromodiethyldimethylbenzene, which show very different disorder diffuse scattering, are given. Procedures for data analysis and

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Section: The Methodsmentioning

confidence: 99%

Scan-truncation corrections in single-crystal diffractometry: an empirical method

Destro¹,

Marsh²

1987

Acta Cryst Sect A

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“…Approximating a solution of this problem, using a convolution of Gaussian and Lorentzian functions (the Voigt method) is rather difficult, so it is more effective to apply the approximations of the Voigt Function. The most popular functions fitted to the experimental data are Pseudo-Voight and Pearson VII, though the Rational Functions (Pyrros & Hubbard, 1983) or some modifications of Lorentzian (Mignot & Rondot, 1976;Young & Wiles, 1982) are also used. In peak shape analysis two more approximations must be considered: a procedure for 0^ fitting or its elimination (Delhez & Mittenmeijer, 1975;Pompa & Zirilli, 1982) and an assumption of angular dependence of fitted parameters (e.g.…”

Section: Introductionmentioning

confidence: 99%

X-Ray Diffraction Profile Analysis of Powdered Samples

Stanisz¹,

Holender²,

Sołtys³

1989

Powder Diffr.

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A quantitative phase analysis often requires advanced numerical studies to determine the appropriate intensity values. In this paper the method of fitting analytical functions to the experimental profile is applied to X-ray powder diffraction patterns obtained with FeK radiation. In the present work, the authors examine some problems connected with numerical studies, especially the function describing the experimental profile. The usefulness of the α2 elimination procedure and the angular dependence FWHM are also examined.

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“…split function is taken as the arithmetic mean of the left and right FWHM parameters . (3) In addition to modeling the diffraction profiles, several other contributions in XRD profiles are also considered. They are a linear background with constant intensity (b) and slope (m) , the scaling factor (S) , and the intensity ratio of the and Q 2 lines (R) .…”

Section: Introductionmentioning

confidence: 99%