Electron-Ion Recombination Rate Coefficients and Photoionization Cross Sections for Astrophysically Abundant Elements. V. Relativistic Calculations for Fe XXIV and Fe XXV for X-Ray Modeling
Electron-Ion Recombination Rate Coefficients and Photoionization Cross Sections for Astrophysically Abundant Elements. V. Relativistic Calculations for Fe XXIV and Fe XXV for X-Ray Modeling
复制标题
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：
10.1086/319187
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
H. L. Zhang
中科院分区：
文献类型：
--
作者：
S. Nahar;A. Pradhan;H. L. Zhang
Photoionization and recombination cross sections and rate coefficients are calculated for Li-like Fe XXIV and He-like Fe XXV using the Breit-Pauli R-matrix (BPRM) method. A complete set of total and level-specific parameters is obtained to enable X-ray photoionization and spectral modeling. The ab initio calculations for the unified (e + ion) recombination rate coefficients include both the nonresonant and the resonant recombination (radiative and dielectronic recombination, RR and DR, respectively) for (e + Fe ) → Fe and (e + Fe ) → Fe . The level-specific rates are computed for all fine-structure levels up to n = 10, enabling accurate computation of recombination-cascade matrices and effective rates for the X-ray lines. The total recombination rate coefficients for both Fe XXIV and Fe XXV differ considerably from the sum of RR and DR rates currently used to compute ionization fractions in astrophysical models. As the photoionization/recombination calculations are carried out using an identical eigenfunction expansion, the cross sections for both processes are theoretically self-consistent; the overall uncertainty is estimated to be about 10%-20%. All data for Fe XXIV and Fe XXV (and also for H-like Fe XXVI, included for completeness) are available electronically.
