Electron-Ion Recombination of Neutral Iron
Electron-Ion Recombination of Neutral Iron
复制标题
中性铁的电子-离子复合
DOI：
--
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
A. Pradhan
中科院分区：
文献类型：
--
作者：
S. Nahar;M. Bautista;A. Pradhan
获得了 Fe I 的总电子离子复合率系数和特定态电子离子复合率系数。计算是使用一种新的从头计算方法进行的，该方法以统一且自洽的方式结合了辐射和双电子复合过程。计算采用紧耦合近似和原子碰撞理论中的 R 矩阵方法。本计算中使用了由 Fe II 的基态 3d64s 和激发态 3d7、3d64p、3d54s2 和 3d54s4p 配置主导的 52 态紧密耦合本征函数展开。通过自电离和辐射通道的显式耦合包括重要的电子关联和辐射阻尼效应。这是对 Fe I 复合率的首次详细原子计算。目前的复合率远高于目前在低温区域（T ≤ 104 K）使用的辐射复合率，而比高温下双电子复合的伯吉斯通式给出的复合率低约 4 倍。研究了新的复合率系数和 Fe I 光电离截面对冷中性星际介质中铁电离结构的影响。结果发现，用新的原子数据获得的 Fe II 与 Fe I 的比率比之前的计算增加了约 3-30 倍。
The total and state-specific electron-ion recombination rate coefficients are obtained for Fe I. The calculations are carried out using a new ab initio method that incorporates both the radiative and the dielectronic recombination processes in an unified and self-consistent manner. The computations employ the close coupling approximation and the R-matrix method from atomic collision theory. A 52 state close coupling eigenfunction expansion dominated by the states of the ground 3d64s and excited 3d7, 3d64p, 3d54s2, and 3d54s4p configurations of Fe II are used in the present calculations. The important electron correlation and radiation damping effects are included via explicit coupling of autoionization and radiative channels. This is the first detailed atomic calculation for the recombination rates for Fe I. The present rates are considerably higher than the radiative recombination rates being used currently in the low-temperature region, T ≤ 104 K, whereas they are about 4 times lower than those given by the Burgess general formula for dielectronic recombination at higher temperatures. The implications of the new recombination rate coefficients and photoionization cross sections for Fe I on the ionization structure of iron in the cold neutral interstellar medium are studied. It is found that the ratio of Fe II to Fe I obtained with the new atomic data increases by a factor of about 3-30 over previous calculations.