The peak in neutron powder diffraction
The peak in neutron powder diffraction
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中子粉末衍射峰
DOI：
10.1107/s0021889884011006
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发表时间：
1984
影响因子：
6.1
通讯作者：
W. Yelon
中科院分区：
文献类型：
--
作者：
B. V. Laar;W. Yelon
为了将Rietveld剖面分析应用于中子粉末衍射数据，需要精确地了解峰剖面的形状和位置。现在使用的方法采用高斯形轮廓，对低角度峰进行半经验不对称校正。积分强度与为x射线计算的经典洛伦兹因子成正比。本文根据衍射仪的几何尺寸给出了峰形的精确表达式。结果表明，该表达式很好地再现了观测峰的不对称性。实验剖面相对于标称布拉格角值的角位移比预期的要大。给出了积分强度对经典洛伦兹因子的修正值。准确的峰剖面表达式已纳入Rietveld剖面分析细化程序。
For the application of Rietveld profile analysis to neutron powder diffraction data a precise knowledge of the peak profile, in both shape and position, is required. The method now in use employs a Gaussian-shaped profile with a semi-empirical asymmetry correction for low-angle peaks. The integrated intensity is taken to be proportional to the classical Lorentz factor calculated for the X-ray case. In this paper an exact expression is given for the peak profile based upon the geometrical dimensions of the diffractometer. It is shown that the asymmetry of observed peaks is well reproduced by this expression. The angular displacement of the experimental profile with respect to the nominal Bragg angle value is larger than expected. Values for the correction to the classical Lorentz factor for the integrated intensity are given. The exact peak profile expression has been incorporated into a Rietveld profile analysis refinement program.