MAGIC-ANGLE THEOREM IN POWDER X-RAY-ABSORPTION SPECTROSCOPY
MAGIC-ANGLE THEOREM IN POWDER X-RAY-ABSORPTION SPECTROSCOPY
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DOI：
10.1103/physrevb.42.37
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发表时间：
1990-07-01
影响因子：
3.7
通讯作者：
LOPEZ, MFR
中科院分区：
文献类型：
--
作者：
PETTIFER, RF;BROUDER, C;LOPEZ, MFR
我们证明，织构效应会严重扭曲粉末样品的X射线吸收数据的测量。我们表明，只要垂直于样品表面的粒子分布函数存在轴对称，并且采用线偏振X射线束，则各向同性平均偶极X射线吸收谱总是可以测量的，而与织构程度无关。为了实现这一点，对同步辐射实验的一个简单修改包括使样品绕垂直于偏振向量和垂直于垂直入射的光束方向的轴旋转θm。θm由Sin 2Θm=1/3给出。
We demonstrate that texture effects can seriously distort the measurement of x-ray-absorption data from powdered specimens. We show that the isotropic average dipolar x-ray-absorption spectrum can always be measured irrespective of the degree of texture, provided axial symmetry in the particle distribution function exists normal to the specimen surface and a linearly polarized x-ray beam is employed. A simple modification to synchrotron-radiation experiments to achieve this consists of rotating the specimen by θ m about an axis perpendicular to the polarization vector and beam direction from normal incidence. θ m is given by sin 2 Θ m= 1/3.