Single-photon single ionization of W+ ions: experiment and theory
Single-photon single ionization of W+ ions: experiment and theory
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DOI：
10.1088/0953-4075/48/23/235203
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发表时间：
2015-09
期刊：
影响因子：
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通讯作者：
A. Müller;S. Schippers;J. Hellhund;J. Hellhund;K. Holste;A. Kilcoyne;R. Phaneuf;C P Ballance;C P Ballance;B. McLaughlin;B. McLaughlin
中科院分区：
文献类型：
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作者：
A. Müller;S. Schippers;J. Hellhund;J. Hellhund;K. Holste;A. Kilcoyne;R. Phaneuf;C P Ballance;C P Ballance;B. McLaughlin;B. McLaughlin
报告了类 Ta (W+) 钨离子光电离的实验和理论结果。使用伯克利先进光源的光子-离子合并光束装置在 16-245 eV 的能量范围内测量绝对横截面。在 16-108 eV 范围内进行了 100 meV 带宽的详细光子能量扫描。此外，在可以观察到精细共振结构的区域中，以 50 meV 分辨率扫描横截面。理论结果是通过狄拉克-库仑 R 矩阵方法获得的。对单电离原子钨离子在 5 s 2 5 p 6 5 d 4 ( 5 D ) 6 s 6 D J , ?> J = 1/2、地能级和相关激发亚稳态能级（J = 3/2、5/2、7/2 和 9/2）进行光电离截面计算。由于实验中使用的离子束必须预期包含来自激发配置的长寿命激发态，因此对第二低项 5 d 5 6 S J , ?> J = 5/2 和 4F 项 5 d 3 6 s 2 4 F J , ?> 进行了额外的截面计算，其中 J = 3/2、5/2、7/2 和 9/2。考虑到 W+ 电子结构的复杂性，计算很好地再现了实验横截面的主要特征。
Experimental and theoretical results are reported for photoionization of Ta-like (W+) tungsten ions. Absolute cross sections were measured in the energy range 16–245 eV employing the photon–ion merged-beam setup at the advanced light source in Berkeley. Detailed photon-energy scans at 100 meV bandwidth were performed in the 16–108 eV range. In addition, the cross section was scanned at 50 meV resolution in regions where fine resonance structures could be observed. Theoretical results were obtained from a Dirac–Coulomb R-matrix approach. Photoionization cross section calculations were performed for singly ionized atomic tungsten ions in their 5 s 2 5 p 6 5 d 4 ( 5 D ) 6 s 6 D J , ?> J = 1/2, ground level and the associated excited metastable levels with J = 3/2, 5/2, 7/2 and 9/2. Since the ion beams used in the experiments must be expected to contain long-lived excited states also from excited configurations, additional cross-section calculations were performed for the second-lowest term, 5 d 5 6 S J , ?> J = 5/2, and for the 4F term, 5 d 3 6 s 2 4 F J , ?> with J = 3/2, 5/2, 7/2 and 9/2. Given the complexity of the electronic structure of W+ the calculations reproduce the main features of the experimental cross section quite well.