Temperature diffuse scattering of nanocrystals.

IF 1.8 4区材料科学

Acta Crystallographica Section A Pub Date : 2012-05-01 Epub Date: 2012-03-29 DOI:10.1107/S0108767312009853

K R Beyerlein, M Leoni, P Scardi

引用次数: 14

Abstract

The effects of thermal vibrations on X-ray powder diffraction patterns are discussed. Special considerations for extremely small crystallites are described, including the occurrence of surface and edge vibrational modes, and a restriction on the maximum phonon wavelength. In doing so, a complete temperature diffuse scattering (TDS) model is presented, which includes the influence of these features on: the Debye-Waller parameter; first-order TDS; and higher-order TDS terms. The importance of using an accurate TDS representation is studied as a function of temperature and crystallite size. It is found that a misrepresentation of the TDS for small crystallites can lead to an error in the determined Debye-Waller parameter on the order of 20-40% and a slight overestimation of the peak broadening. While the presented theory is primarily developed considering X-ray scattering, the same expressions are expected to describe the TDS in faster-than-sound neutron powder diffraction measurements.

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纳米晶体的温度扩散散射。

讨论了热振动对x射线粉末衍射图的影响。描述了极小晶体的特殊考虑，包括表面和边缘振动模式的发生，以及最大声子波长的限制。在此基础上，提出了一个完整的温度扩散散射(TDS)模型，其中包括这些特征对Debye-Waller参数的影响;一阶TDS;和高阶TDS项。研究了使用精确的TDS表示作为温度和晶粒尺寸的函数的重要性。结果发现，对小晶的TDS的错误表示会导致确定的Debye-Waller参数的误差在20-40%左右，并且对峰展宽的估计略高。虽然提出的理论主要是考虑x射线散射，但期望相同的表达式描述超声中子粉末衍射测量中的TDS。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Acta Crystallographica Section A 化学-晶体学

自引率

11.10%

发文量

审稿时长

3 months

期刊介绍： Acta Crystallographica Section A: Foundations and Advances publishes articles reporting advances in the theory and practice of all areas of crystallography in the broadest sense. As well as traditional crystallography, this includes nanocrystals, metacrystals, amorphous materials, quasicrystals, synchrotron and XFEL studies, coherent scattering, diffraction imaging, time-resolved studies and the structure of strain and defects in materials. The journal has two parts, a rapid-publication Advances section and the traditional Foundations section. Articles for the Advances section are of particularly high value and impact. They receive expedited treatment and may be highlighted by an accompanying scientific commentary article and a press release. Further details are given in the November 2013 Editorial. The central themes of the journal are, on the one hand, experimental and theoretical studies of the properties and arrangements of atoms, ions and molecules in condensed matter, periodic, quasiperiodic or amorphous, ideal or real, and, on the other, the theoretical and experimental aspects of the various methods to determine these properties and arrangements.