Theory of polarization-averaged core-level molecular-frame photoelectron angular distributions: I. A full-potential method and its application to dissociating carbon monoxide dication
Theory of polarization-averaged core-level molecular-frame photoelectron angular distributions: I. A full-potential method and its application to dissociating carbon monoxide dication
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DOI：
10.1088/1361-6455/abd06d
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发表时间：
2020-12
期刊：
影响因子：
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通讯作者：
F. Ota;K. Yamazaki;D. Sébilleau;K. Ueda;K. Hatada
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文献类型：
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作者：
F. Ota;K. Yamazaki;D. Sébilleau;K. Ueda;K. Hatada
我们提出了从离解双离子一氧化碳 CO2+ 的氧原子 1s 轨道发射的偏振平均分子框架光电子角分布 (PA-MFPAD) 的理论研究。由于偏振平均，去除了对 MFPAD 贡献最大的光电子直达波的贡献，使得 PA-MFPAD 清晰地显示光电子散射图像的细节。因此，有必要采用准确的理论来对连续态进行理论分析。在这项研究中，我们应用全势多重散射理论，将空间划分为 Voronoi 多面体和截断球体，以考虑物理原子球体外部的电子电荷密度。我们不使用单元形状函数的球谐展开来避免发散问题。采用多构型二阶微扰理论限制活性空间法计算散射单元中的电势，考虑核心空穴对最终状态电子电荷密度的影响，从而实现真实的弛豫。我们表明，全电位处理在光电子动能为 100 eV 的 PA-MFPAD 中发挥着重要作用。相比之下，PA-MFPAD 对俄歇终态中的任何类型的主要激发态都不敏感。我们还研究了 CO2+ 解离的动力学。我们发现 PA-MFPAD 的形状会随着 C-O 键长的变化而发生显着变化。
We present a theoretical study of the polarization-averaged molecular-frame photoelectron angular distributions (PA-MFPADs) emitted from the 1s orbital of oxygen atoms of dissociating dicationic carbon monoxide CO2+. Due to the polarization average, the contribution of the direct wave of the photoelectron, which represents the largest contribution to the MFPADs, is removed, so that the PA-MFPADs clearly show the details of the scattering image of the photoelectron. As a result, it is necessary to employ an accurate theory for the theoretical analysis of the continuum state. In this study, we apply a full-potential multiple scattering theory, where the space is partitioned into Voronoi polyhedra and truncated spheres, to take into account the electron charge density outside the physical atomic spheres. We do not use the spherical harmonic expansion of the cell shape functions to avoid divergence problems. The potentials in the scattering cells are computed using the multiconfigurational second-order perturbation theory restricted active space method to take into account the influence of the core hole in the electron charge density in the final state, so that a realistic relaxation can be achieved. We show that the full-potential treatment plays an important role in the PA-MFPADs at a photoelectron kinetic energy of 100 eV. In contrast, the PA-MFPADs are not sensitive to any type of major excited states in the Auger final state. We also study the dynamics of the CO2+ dissociation. We find that the PA-MFPADs dramatically change their shape as a function of the C–O bond length.