On the Integrated Intensity of X‐Ray Diffraction in Crystals with Randomly Distributed Defects

Abstract

The dynamical theory of X-ray diffraction in crystals with randomly distributed small defects based on an optical coherence formalism is used for calculations of integrated reflectivities (in the Laue case) of crystals with statistically placed small precipitates. It is shown that in the case of thinner crystals the integrated reflectivity is influenced mainly by the diffuse scattering, which increases the integrated reflectivity, for thicker crystals a decreasing effect of the diffuse absorption dominates. The calculated thickness dependences of integrated reflectivities are proved experimentally by projection topography of wedge-shaped crystals with growth striations containing precipitates.Dynamische Theorie der Rontgenbeugung in Kristallen mit statistisch verteilten Defekten wird zur Berechnung der integralen Reflektivitat von Kristallen mit kleinen Prazipitaten verwendet. Es wird gezeigt, dafi im Falle dunner Kristalle die integrale Reflektivitat uberwiegend durch diffuse Streuung beeinflufit wird, die die integrale Reflektivitat vergrofiert. Fur dickere Kristalle ist der Effekt der diffusen Absorption dominant. Die berechneten AbhPngigkeiten der integralen Reflektivitaten von der Kristalldicke werden durch die Projektionstopographie eines keilformigen Kristalls mit Wachstumstreifen bewiesen.

Быстрые Приповерхностные Изменения Дефектной Структуры В Кристаллах Тетрабората Лития Во Внешнем Электрическом Поле

“…Параметр ширины пика на полувысоте -полуширина (FWHM) и интегральная интенсивность (сумма по углу упругой когерентной дифракционной составляющей и неупругого диффузного рассеяния на дефектах) -является одной из основных характеристик степени совершенства кристалла, угол Брэгга связан с параметром решетки. По вариации данных параметров можно судить об изменениях реальной структуры кристалла [32][33][34].…”

X-Ray Dynamical Diffraction by Quasi-Monolayer Graphene

“…At the same time, Holý proposed another variant of dynamical theory based on the optical coherence formalism [25][26][27][28] and applied this approach for determining the parameters of the single crystals' microdefects [29][30][31]. In addition, the distorted wave Born approximation was used for calculation of scattering patterns for the case when the microdefects are contained in the thin crystalline layers [32].…”

Dynamical effects in the integrated X-ray scattering intensity from imperfect crystals in Bragg diffraction geometry. II. Dynamical theory

“…At the same time, alternative dynamical theories were developed for the description of both the differential and integrated intensities of X-ray diffraction. Namely, the theory based on the optical coherence formalism (Holý, 1982a(Holý, ,b, 1983(Holý, , 1984Holý & Kubě na, 1987) was applied to the X-ray characterization of crystals containing microdefects (Holý & Kubě na, 1987, 1989, 1992. Also, the distorted wave Born approximation (DWBA) was applied to the simulation of reciprocal-space maps for thin, slightly distorted crystalline layers with microdefects (Holý et al, 1999).…”