Mayer Dennis, Handrich Max, Picconi David, Lever Fabiano, Mehner Lisa, Murillo-Sanchez Marta L, Walz Constantin, Titov Evgenii, Bozek John, Saalfrank Peter, Gühr Markus
Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.
J Chem Phys. 2024 Oct 7;161(13). doi: 10.1063/5.0226983.
We present a comprehensive, combined experimental and theoretical study of the core-level photoelectron and near-edge x-ray absorption fine structure (NEXAFS) spectra of 2-thiouracil, 4-thiouracil, and 2,4-dithiouracil at the oxygen 1s, nitrogen 1s, carbon 1s, and the sulfur 2s and 2p edges. X-ray photoelectron spectra were calculated using equation-of-motion coupled-cluster theory (EOM-CCSD), and NEXAFS spectra were calculated using algebraic diagrammatic construction and EOM-CCSD. For the main peaks at O and N 1s as well as the S 2s edge, we find a single photoline. The S 2p spectra show a spin-orbit splitting of 1.2 eV with an asymmetric vibrational line shape. We also resolve the correlation satellites of these photolines. For the carbon 1s photoelectrons, we observe a splitting on the eV scale, which we can unanimously attribute to specific sites. In the NEXAFS spectra, we see very isolated pre-edge features at the oxygen 1s edge; the nitrogen edge, however, is very complex, in contrast to the XPS findings. The C 1s edge NEXAFS spectrum shows site-specific splitting. The sulfur 2s and 2p spectra are dominated by two strong pre-edge transitions. The S 2p spectra show again the spin-orbit splitting of 1.2 eV.
我们对2-硫尿嘧啶、4-硫尿嘧啶和2,4-二硫尿嘧啶在氧1s、氮1s、碳1s以及硫2s和2p边缘的芯能级光电子能谱和近边X射线吸收精细结构（NEXAFS）光谱进行了全面的实验与理论相结合的研究。使用运动方程耦合簇理论（EOM-CCSD）计算X射线光电子能谱，使用代数图示构建法和EOM-CCSD计算NEXAFS光谱。对于O和N 1s以及S 2s边缘的主峰，我们发现了单一的光电子线。S 2p光谱显示出1.2 eV的自旋轨道分裂，具有不对称的振动线形。我们还解析了这些光电子线的相关卫星峰。对于碳1s光电子，我们观察到在eV尺度上的分裂，我们一致将其归因于特定的位点。在NEXAFS光谱中，我们在氧1s边缘看到非常孤立的预边特征；然而，与XPS结果相反，氮边缘非常复杂。C 1s边缘NEXAFS光谱显示出位点特异性分裂。硫2s和2p光谱由两个强预边跃迁主导。S 2p光谱再次显示出1.2 eV的自旋轨道分裂。
