涉及S2p、F1s和S1s内壳层的SF6的芯价双电离
Core-valence double ionization of SF6 involving S2p, F1s and S1s inner shells
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中文总结 AI 辅助
本文研究SF6的S2p、F1s、S1s芯价双电离，推导CV能谱强度模型，结合实验与计算揭示芯空穴对电子结构的影响，实现谱线详细归属。
中文摘要 AI 辅助
本文报道、分析并对比了SF6的S2p、F1s和S1s边附近的芯价双电离电子能谱，与常规价层光电子能谱及量子化学计算结果进行了比较。芯价能谱在能量上被展宽，在15至40 eV之间呈现出足够分离的显著结构，可用于分子轨道分析。这些能谱为电子结构提供了新的见解，表明芯空穴会显著重排分子轨道能级顺序，该效应可追溯至轨道定域性、节点结构以及价层到芯层的穿透作用。在所有三种芯价能谱中，双电离态的单重态和三重态分裂随芯层加深逐渐减小，S2p对应的分裂比S1s更大，这反映出S2p存在更强的价层到芯层穿透作用和交换相互作用。总体而言，分子轨道（MO）解释在冻结或自洽场（SCF）近似下成立，仅F1s能谱的内层部分需要通过MO分解效应进行分析。本文采用独立通道方法推导了芯价（CV）能谱的强度模型，其中初级芯电离通过与连续态的偶极耦合处理，价电子通过 shake-off 过程被激发至第二个连续态，同时保持离散双电离态与两个连续电子之间的完整自旋耦合和自旋选择性。初级分子光电子强度通过相关分子轨道的单中心原子轨道投影表示为原子亚壳层截面的加权和。计算得到的能谱与实验结果吻合良好，可实现详细的谱线归属，尤其识别并讨论了F1s芯电离位点的对称性破缺现象。
英文摘要
Core-valence double ionization electron spectra near the S2p, F1s and S1s edges of SF6 are presented, analyzed and compared with conventional valence photoelectron spectra and quantum chemical calculations. The core-valence spectra are energetically stretched out, revealing salient structures between 15 and 40 eV that are sufficiently separated for molecular orbital analysis. The spectra offer new insights into the electronic structure, showing that the core hole substantially rearranges the molecular orbital order. This effect can be traced to orbital localization and nodal structure, as well as to valence-to-core penetration. The singlet and triplet splittings of the dicationic states progressively decrease in all three core-valence spectra towards deeper core levels, with larger splittings for S2p than S1s, reflecting greater valence-to-core penetration and exchange interaction for S2p. By large, the MO interpretation holds in frozen or self-consistent-field representations, except for the inner parts of the F1s spectra, which require analysis in terms of MO breakdown effects. An intensity model for CV spectra is derived using an independent-channel approach, where primary core ionization is treated by dipolar coupling to a continuum and the valence electron is promoted to a second continuum through shake-off. Full spin coupling and spin selectivity between the discrete doubly ionized states and the two continuum electrons are maintained. The primary molecular photoelectron intensity is expressed as a weighted sum of atomic subshell cross sections using a one-center atomic orbital projection of the relevant molecular orbital. The calculated spectra agree well with experiment and allow detailed assignment. In particular, symmetry breaking at the F1s core-ionization site is identified and discussed.
