Non-resonant inelastic X-ray scattering (NRIXS) is a new technique for atomic and molecular physics that allows one to measure the electronic structures and dynamic parameters of the ground and excited states of atoms and molecules in momentum space. There is a clearly understood physical picture of NRIXS, which reveals its remarkable advantages of satisfying the first Born approximation and being able to excite dipole-forbidden transitions. Various physical properties of atoms and molecules, such as their elastic and inelastic squared form factors, optical oscillator strengths, and Compton profiles, can be explored using NRIXS under different experimental conditions. In this paper, we review newly developed experimental methods for NRIXS, together with its characteristics and various applications, with emphasis on the new insights into excitation mechanism and other new information revealed by this technique. The intrinsic connections and differences between NRIXS and fast electron impact spectroscopy are elucidated. Future applications of this method to atomic and molecular physics are also described.

中文翻译：

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非共振非弹性 X 射线散射光谱：一种用于检测原子和分子电子结构的动量探针

非共振非弹性 X 射线散射 (NRIXS) 是原子和分子物理学的一项新技术，它允许人们测量动量空间中原子和分子的基态和激发态的电子结构和动态参数。NRIXS 有一个清晰的物理图片，它揭示了它满足第一波恩近似和能够激发偶极子禁止跃迁的显着优势。可以在不同实验条件下使用 NRIXS 探索原子和分子的各种物理特性，例如它们的弹性和非弹性平方形状因子、光学振荡器强度和康普顿分布。在本文中，我们回顾了新开发的 NRIXS 实验方法，及其特性和各种应用，重点是对激发机制的新见解和该技术揭示的其他新信息。阐明了 NRIXS 和快速电子撞击光谱之间的内在联系和差异。还描述了这种方法在原子和分子物理学中的未来应用。