X‐ray absorption spectroscopy represents a valuable characterization tool for complex materials like multialkali antimonides. The interpretation of such experimental results greatly benefits from state‐of‐the‐art theoretical references. In a first‐principles work based on density‐functional theory and many‐body perturbation theory, the fingerprints of X‐ray absorption near‐edge structure (XANES) of Cs₃Sb from the Cs K‐ and L₃‐edge are unraveled. From the electronic structure and the orbital character of the conduction bands, the contributions to the XANES spectra from the two inequivalent Cs atoms in the adopted stoichiometric unit cell are analyzed. The predominant weight of Cs s‐ and d‐electrons in the unoccupied region anticipates the relatively high signal yielded by the L₃‐edge. Clear atomic signatures, in the form of a pronounced excitonic peak, are visible in the Cs K‐edge spectra. In the XANES from the L₃‐edge, both Cs atoms yield similar contributions, which are yet distinguishable in the presented calculations. Quantitative analysis enabled by the adopted methodology reveals that electron–hole correlation effects manifest themselves mainly through a redistribution of the oscillator strength to lower energies, whereas exciton binding energies are on the order of a few hundred meV.

中文翻译：

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Cs3Sb中Cs原子的X射线吸收指纹图谱

X射线吸收光谱法是用于复杂材料（如多碱金属锑化物）的有价值的表征工具。对此类实验结果的解释极大地受益于最新的理论参考。在基于密度泛函理论和多体摄动理论的第一性原理研究中，从Cs K和L ₃边缘解开了Cs ₃ Sb的X射线吸收近边缘结构（XANES）的指纹。从导带的电子结构和轨道特性，分析了所采用的化学计量单位晶格中两个不等价的Cs原子对XANES光谱的贡献。在无人区中，Cs s和d电子的主要重量预示着L会产生相对较高的信号₃边缘。在Cs K边谱中可以看到明显的激子峰形式的清晰原子特征。在L ₃边缘的XANES中，两个Cs原子产生相似的贡献，但在所提供的计算中仍可区分。通过采用的方法进行的定量分析表明，电子-空穴相关效应主要通过将振荡器强度重新分配给较低的能量而表现出来，而激子结合能约为数百meV。