Extended range X-ray pair distribution functions
Extended range X-ray pair distribution functions
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DOI：
10.1016/j.nima.2019.163318
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发表时间：
2020-03-01
影响因子：
1.4
通讯作者：
Weber, J. K. R.
中科院分区：
文献类型：
--
作者：
Benmore, C. J.;Alderman, O. L. G.;Weber, J. K. R.
在这里，我们描述了一个双探测器系统的高能X射线，同时，小和广角X射线散射（SAXS和WAXS），旨在提取扩展范围对分布函数（ER-PDF）的无序材料。硬件和软件提供了连续的倒易空间覆盖范围从原子到纳米尺度。不同的分辨率，拼接的数据和归一化的绝对规模的细节进行了概述。此外，SAXS和WAXS理论的结合被认为是为了使跨越多个长度尺度的结构因子直接傅立叶变换到真实的空间。ER-PDF和对距离分布函数（PDDF）表示之间的重要区别被证明。结果表明，当结构因子S（Q）中的SAXS强度与WAXS强度相似时，对ER-PDF的贡献最小。然而，当SAXS S（Q）强度明显强于WAXS时，ER-PDF可以提供局部、中间和纳米尺度上的重要结构信息。值得注意的是，ER-PDF方法提供了关于颗粒尺寸及其密度分布的直接信息，克服了密集堆积系统的PDDF分析的局限性。
Here we describe a dual detector system for high-energy X-ray, simultaneous, small and wide-angle X-ray scattering (SAXS and WAXS), designed to extract extended-range pair distribution functions (ER-PDF) for disordered materials. The hardware and software provides continuous reciprocal space coverage over atomic to nanometer length-scales. Details of the varying resolution, splicing of data and normalization on an absolute scale are outlined. In addition, the combination of SAXS and WAXS theory is considered with a view to enabling a direct Fourier transformation of the structure factor spanning multiple length-scales into real space. Important distinctions between the ER-PDF and the pair distance distribution function (PDDF) representations are demonstrated. It is shown that when the SAXS intensity in the structure factor, S(Q), is similar to the WAXS intensity, the contributions to the ER-PDF are minimal. However, when the SAXS S(Q) intensities are substantially stronger than the WAXS, the ER-PDF can provide important structural information on the local, intermediate and nanometer length-scales. Notably, the ER-PDF method provides direct information on particle sizes and their density distributions, overcoming the limitations of PDDF analysis for densely packed systems.