Properties of X-ray resonant scattering in the Bragg case revealed on the Riemann surface

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• 作者：Takashi Saka
• 关键词：X-ray diffraction ; dynamical theory ; Bragg case ; Riemann surface ; dispersion surface ; rocking curve ; resonant scattering
• 刊名：Acta Crystallographica Section A
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：72
• 期：4
• 页码：472-479
• 全文大小：493K
• ISSN：1600-5724

文摘

Continuing the work described in the previous paper [Saka (2016). Acta Cryst. A72, 338–348], the dynamical theory for perfect crystals in the Bragg case is reformulated using the Riemann surface. In particular, diffraction under resonant scattering conditions is investigated. The characteristic features of the dispersion surface and the rocking curve are analytically revealed using four parameters, which are the real and imaginary parts of two quantities specifying the degree of departure from the exact Bragg conditions and the reflection strength. Characteristic properties that have been deduced through numerical analysis are derived analytically using these four parameters. Visualization of the geometric relationships between the four parameters on the Riemann surface is useful for understanding many properties such as symmetry and sharpness of the rocking curve under special conditions. Therefore, employing the Riemann surface is instructive for numerical analysis and useful for understanding dynamical diffraction in the Bragg case.