The several mathematical formulations of X-ray diffraction theory facilitate its understanding and use as a materials characterization technique, since one can opt for the simplest formulation that adequately describes the case being studied. As synchrotrons advance, new techniques are developed and there is a need for simple formulations to describe them. One of these techniques is soft resonant X-ray diffraction, in which the X-rays suffer large attenuation due to absorption. In this work, an expression is derived for the X-ray diffraction profiles of reflections where the linear absorption is far greater than primary extinction; in other words, the crystal is superabsorbing. The case is considered of a parallel plate crystal, for which the diffraction profile of the superabsorbing crystal is computed as a function of crystal size normal to the diffraction planes. For thin crystals or those with negligible absorption, the diffraction profile of a superabsorbing crystal coincides with the result of the kinematical theory. For thick crystals, the absorption intrinsic profile is obtained, described by a Lorentzian function and characterized by the absorption intrinsic width. This absorption intrinsic width is proportional to the linear absorption coefficient and its expression is similar to that for the Darwin width, while the absorption intrinsic profile is a special case of the Laue dynamical theory, and it is similar to the Ornstein–Zernike Lorentzian. The formulation of X-ray diffraction of superabsorbing crystals is simple and provides new perspectives for the soft resonant X-ray diffraction technique.

中文翻译：

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超吸收晶体中的 X 射线衍射：吸收本征宽度

X 射线衍射理论的几种数学公式有助于其理解和用作材料表征技术，因为人们可以选择最简单的公式来充分描述所研究的情况。随着同步加速器的进步，新技术不断发展，需要简单的公式来描述它们。这些技术之一是软共振X射线衍射，其中X射线由于吸收而遭受很大的衰减。在这项工作中，推导了反射的 X 射线衍射剖面的表达式，其中线性吸收远大于初级消光；换句话说，水晶具有超强的吸光性。考虑平行板晶体的情况，其中超吸收晶体的衍射轮廓被计算为垂直于衍射平面的晶体尺寸的函数。对于薄晶体或吸收可忽略不计的晶体，超吸收晶体的衍射剖面与运动学理论的结果一致。对于厚晶体，可以获得吸收本征分布，由洛伦兹函数描述并由吸收本征宽度表征。该吸收本征宽度与线性吸收系数成正比，其表达式与达尔文宽度的表达式类似，而吸收本征轮廓是劳厄动力学理论的特例，与Ornstein-Zernike Lorentzian 类似。超吸收晶体的X射线衍射公式简单，为软共振X射线衍射技术提供了新的视角。