Computation of Resonant Inelastic X-Ray Scattering in the condensed phase across the whole periodic table

共振非弹性x射线散射（RIXS）允许详细了解分子物种的电子结构。由于现代同步辐射光源的安装，近年来它得到了迅速的发展。然而，RIXS和其他x射线光谱技术的相似之处在于，如果没有理论的帮助，很难解释它们的光谱。通过结合德国和法国合作伙伴的专业知识，我们旨在解决轻元素，过渡金属配合物和凝聚态重元素系统中RIXS光谱的精确计算。为此，我们提出了基于密度泛函理论（DFT）和相对论运动方程耦合聚类理论的实时响应方法，用于RIXS光谱的计算。为了考虑溶剂和晶体环境，这些方法将与基于冷冻密度嵌入形式的量子化学嵌入方法相结合。这些新颖的计算方法将应用于实验相关的测试案例，包括整个元素周期表中的元素，即溶液中的氨基酸，铁配合物和凝聚相中的铀酰物种。

Resonant Inelastic X-ray Scattering (RIXS) allows for detailed insights into the electronic structure of molecular species. Owing to the installation of modern synchrotron radiation sources, it has seen rapid development in recent years. RIXS and other X-ray spectroscopic techniques, however, are alike in that it is very difficult to interpret their spectra without aid from theory. By combining the expertise of the German and French partners, we aim at addressing the accurate calculation of RIXS spectra in light elements, in transition metal complexes, and heavy element systems in the condensed phase. To this end, we propose the development of real-time response methods based on density-functional theory (DFT) and on relativistic equation-of-motion coupled cluster theory for the calculation of RIXS spectra. To account for solvent and crystal environments, these approaches will be combined with quantum-chemical embedding methods based on the frozen-density embedding formalism. These novel computational approaches will be applied to experimentally relevant test cases featuring elements across the whole periodic table, namely amino acids in solution, iron complexes, and uranyl species in the condensed phase.