Electron-Ion Recombination Rate Coefficients and Photoionization Cross Sections for Astrophysically Abundant Elements. XI. N V-VI and F VII-VIII for Ultraviolet and X-Ray Modeling
Electron-Ion Recombination Rate Coefficients and Photoionization Cross Sections for Astrophysically Abundant Elements. XI. N V-VI and F VII-VIII for Ultraviolet and X-Ray Modeling
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天体物理丰富元素的电子-离子复合率系数和光电离截面。
DOI：
10.1086/501503
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
S. Nahar
中科院分区：
文献类型：
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作者：
S. Nahar
用自洽统一方法研究了hν + N Participate N + e，hν + N Participate N + e，hν + F Participate F + e和hν + F Participate F + e的光电离和电子-离子复合的逆过程.该方法能够计算总的和特定能级的复合速率系数αR和αR（i），包括辐射复合和双电子复合（RR和DR）。在紧耦合近似下，采用R矩阵方法，对两个过程采用相同的波函数展开，计算了光电离和复合截面σPI和σRC。计算结果包括所有精细结构能级的总光电离截面和部分光电离截面以及复合速率系数，其中n ≤ 10，类锂N-V和F-VII（1/2 ≤ J ≤ 17/2）约为100，类氦N-VI和F-VIII（0 ≤ J ≤ 10）超过170.首次计算了这些离子的能级特异性σPI（nSLJ）和αR（T; nSLJ）。N V和F VII的耦合通道波函数展开分别由核N VI和F VIII的17个能级组成，并且N VI和F VIII分别由核N VII和F IX的16个能级组成。相对论精细结构被认为是通过Breit-Pauli R-矩阵方法。在天体物理和实验室等离子体应用中，给出了在扩展温度范围内的单值总αR（T）。虽然所有离子的总统一αR（T）与已发表的RR+DR率一致，但在NV的DR峰处有显著差异。总σRC（E）和αR（E）作为光电子能量的函数，与实验进行比较。为了完整性，也给出了类H的N VII和F IX的总速率。截面σPI和σRC包含了辐射阻尼、通道耦合、DR和RR的干扰等重要原子效应，应精确到10%-15%。综合数据集适用于紫外线和X射线线的电离平衡和复合级联模型。
The inverse processes of photoionization and electron-ion recombination for hν + N ↔ N + e, hν + N ↔ N + e, hν + F ↔ F + e, and hν + F ↔ F + e are studied in detail using a self-consistent unified method for the total electron-ion recombination. The method enables calculation of the total and level-specific recombination rate coefficients αR and αR(i), subsuming both radiative and dielectronic recombination (RR and DR). The photoionization and recombination cross sections σPI and σRC are computed using an identical wave function expansion for both processes in the close coupling approximation using the R-matrix method. The results include total and partial photoionization cross sections and recombination rate coefficients for all fine-structure levels up to n ≤ 10, about 100 for Li-like N V and F VII with 1/2 ≤ J ≤ 17/2, and over 170 for He-like N VI and F VIII with 0 ≤ J ≤ 10. Level-specific σPI(nSLJ) and αR(T; nSLJ) are calculated for the first time for these ions. The coupled-channel wave function expansions for N V and F VII consist of 17 levels of cores N VI and F VIII, respectively, and for N VI and F VIII consist of 16 levels of cores N VII and F IX, respectively. Relativistic fine structure is considered through the Breit-Pauli R-matrix method. The single-valued total αR(T) is presented over an extended temperature range for astrophysical and laboratory plasma applications. Although the total unified αR(T) for all ions agree well with the available published RR+DR rates, significant differences are noted at the DR peak for N V. Total σRC(E) and αR(E) as functions of photoelectron energy are presented for comparison with experiments. Total rates for H-like N VII and F IX are also given for completeness. The cross sections σPI and σRC include important atomic effects such as radiation damping, channel couplings, and interference of DR and RR, and should be accurate to within 10%-15%. The comprehensive data sets are applicable for ionization balance and recombination-cascade models for UV and X-ray lines.