THE APPROXIMATION OF ASYMMETRIC NEUTRON POWDER DIFFRACTION PEAKS BY SUMS OF GAUSSIANS
THE APPROXIMATION OF ASYMMETRIC NEUTRON POWDER DIFFRACTION PEAKS BY SUMS OF GAUSSIANS
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DOI：
10.1107/s0021889882012783
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发表时间：
1982-01-01
影响因子：
6.1
通讯作者：
HOWARD, CJ
中科院分区：
文献类型：
--
作者：
HOWARD, CJ
中子粉末衍射仪在大的垂直计数器接受角下工作时产生的衍射图样中，峰被移动和加宽，并且可能变得明显不对称。结果表明，高斯的总和一般提供了一个很好的近似这些峰值。高斯的总和已被包括作为现有的轮廓细化程序中的轮廓的可选描述。在该应用中，该总和包含单个不对称参数，该不对称参数可以从衍射仪几何形状估计或在细化中确定。建议在描述不对称峰时，使用高斯和代替简单的高斯乘以Rietveld的半经验不对称因子。
Neutron powder diffractometers operating with large vertical counter acceptance angles produce diffraction patterns in which the peaks are shifted and broadened, and may become distinctly asymmetric. It is shown that a sum of Gaussians generally provides a good approximation to these peaks. The sum of Gaussians has been included as an optional description of the profile within an existing profile refinement program. In this application, the sum incorporates a single asymmetry parameter which can be estimated from the diffractometer geometry or determined in the refinement. It is recommended that, in describing asymmetric peaks, the sum of Gaussians be used in place of the simple Gaussian multiplied by Rietveld's semi-empirical asymmetry factor.