Abstract This report presents i) various characteristic features in photoionization cross sections (σPI) of Cl II + hν → Cl III + e for many fine structure levels of Cl II, 392 in total with n ≤ 10 and l ≤ 9, ii) comparison of features with those observed in an experiment carried out at the Advanced Light Source at Lawrence Berkeley National Lab, and iii) partial photoionization cross sections of the ground level for ionization leaving the core ion in to various excited levels for applications in plasma modeling. The features correspond to resonant structures, the shape of the background, and their interference effect in σPI of this near neutral ion Cl II with 16 electrons. σPI for the 5 levels of the ground configuration 3s23p4(3P0,1,2, 1D2, 1S0) of Cl II show regions of narrow Rydberg resonances at and near threshold energies, and resonant structures at higher energies in contrast to typical smooth decrease in the background. Various other features in σPI of levels of excited equivalent electron states and broad Seaton resonances in single valence electron excited levels are illustrated with examples. Comparison of calculated σPI of the 15 lowest levels with the combined features of the measured photoionization spectrum shows excellent agreement by reproducing and thus identifying them to the levels that they belong to. The calculations were carried out in relativistic Breit-Pauli R-matrix (BPRM) method using a close coupling wave function expansion of 45 levels up to 4s of the core ion Cl III. These levels were optimized using a set of 12 configurations going up to orbital 5s, 3s23p3, 3s3p4, 3p5, 3s23p23d, 3s23p24s, 3s23p24p, 3s23p24d, 3s23p24f, 3s23p25s, 3s3p33d, 3s23p3d2, 3p43d producing 283 levels of Cl III. The autoionizing resonances are delineated with a fine energy mesh to observe the fine structure effects. The present results will provide high precision parameters for various applications involving this less studied ion.

中文翻译：

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Cl II 的地面和激发能级的光电离特征和实验基准

摘要 本报告介绍了 i) Cl II + hν → Cl III + e 的光电离截面 (σPI) 的各种特征，对于 Cl II 的许多精细结构水平，总共 392，n ≤ 10 和 l ≤ 9，ii) 比较在劳伦斯伯克利国家实验室的高级光源进行的实验中观察到的特征，以及 iii) 用于电离的地平面的部分光电离横截面，使核心离子处于各种激发水平，以用于等离子体建模。这些特征对应于共振结构、背景形状以及它们在具有 16 个电子的近中性离子 Cl II 的 σPI 中的干扰效应。Cl II 的地面配置 3s23p4(3P0,1,2, 1D2, 1S0) 的 5 个能级的 σPI 显示在阈值能量处和附近的窄里德堡共振区域，与背景中典型的平滑下降相比，更高能量下的共振结构。示例说明了激发等效电子态能级的 σPI 和单价电子激发能级中的宽西顿共振的各种其他特征。将 15 个最低水平的计算 σPI 与测得的光电离谱的组合特征进行比较，通过再现并因此将它们识别为它们所属的水平，显示出极好的一致性。计算是在相对论 Breit-Pauli R 矩阵 (BPRM) 方法中进行的，使用核心离子 Cl III 的 45 级高达 4s 的紧密耦合波函数展开。这些级别使用一组 12 种配置进行了优化，最高轨道为 5s、3s23p3、3s3p4、3p5、3s23p23d、3s23p24s、3s23p24p、3s23p24d、3s23p24f、3s23p23p 3s23p3d2、3p43d 产生 283 个水平的 Cl III。自电离共振用精细的能量网格描绘，以观察精细的结构效应。目前的结果将为涉及这种研究较少的离子的各种应用提供高精度参数。