Atomic data calculations for Au i –Au iii and exploration in the application of collisional-radiative theory to laboratory and neutron star merger plasmas
Atomic data calculations for Au i –Au iii and exploration in the application of collisional-radiative theory to laboratory and neutron star merger plasmas
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Au i – Au iii 的原子数据计算以及碰撞辐射理论在实验室和中子星合并等离子体中的应用探索
DOI：
10.1093/mnras/stab3285
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发表时间：
2021
影响因子：
4.8
通讯作者：
Ballance, C P
中科院分区：
文献类型：
--
作者：
McCann, Michael;Bromley, S;Loch, S D;Ballance, C P
中子双星合并长期以来一直被认为是足够丰富的中子环境，可以支持快速中子捕获元素（r过程元素）的合成，例如金。然而，文献表明，除了中性和单电离系统之外，对于合并重要的其余离子阶段的原子数据不完整。在这项工作中，我们报告了使用 grasp0 代码对 Aui-Auiii 进行相对论原子结构计算。与使用灵活原子代码的计算进行比较表明，Aui-Auiii 能级能量的平均不确定性分别为 9.2%、5.7% 和 3.8%。我们计算的 A 值与文献（如果有）中的值之间达成了约 50% 的一致性。利用 Aui 的 grasp0 结构，我们计算了电子碰撞激发速率系数，并使用碰撞辐射模型探索中子星并合环境中可能的激发动力学和线比诊断。我们发现，正确计算亚稳态群体对于从 Aui 的紫外-可见线比诊断中提取有用信息至关重要。作为对我们数据的测试，我们应用电子撞击数据来研究文献中的金空心阴极光谱，并将等离子体条件诊断为 Te= 3.1 ± 1.2 eV 和 cm−3。
Neutron binary star mergers have long been proposed as sufficiently neutron rich environments that could support the synthesis of rapid neutron capture elements (r-process elements) such as gold. However, the literature reveals that beyond neutral and singly ionized systems, there is an incompleteness of atomic data for the remaining ion stages of importance for mergers. In this work, we report on relativistic atomic structure calculations for Aui–Auiiiusing thegrasp0codes. Comparisons to calculations using the Flexible Atomic Code suggest uncertainties on average of 9.2 per cent, 5.7 per cent, and 3.8 per cent for Aui–Auiiilevel energies. Agreement around ∼50 per cent is achieved between our computedA-values and those in the literature, where available. Using thegrasp0structure of Aui, we calculated electron-impact excitation rate coefficients and use a collisional-radiative model to explore the excitation dynamics and line ratio diagnostics possible in neutron star merger environments. We find that proper accounting of metastable populations is critical for extracting useful information from ultraviolet–visible line ratio diagnostics of Aui. As a test of our data, we applied our electron-impact data to study a gold hollow cathode spectrum in the literature and diagnosed the plasma conditions asTe= 3.1 ± 1.2 eV andcm−3.