Energy levels, radiative rates and electron impact excitation rates for transitions in He-like Ti XXI, V XXII, Cr XXIII and Mn XXIV
Energy levels, radiative rates and electron impact excitation rates for transitions in He-like Ti XXI, V XXII, Cr XXIII and Mn XXIV
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DOI：
10.1088/0031-8949/85/06/065301
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发表时间：
2012-06
期刊：
影响因子：
2.9
通讯作者：
K. Aggarwal;F. Keenan
中科院分区：
文献类型：
--
作者：
K. Aggarwal;F. Keenan
我们报告计算的能级，辐射率和电子碰撞激发截面和率的过渡在He类Ti XXI，V XXII，Cr XXIII和Mn XXIV。采用GRASS（通用相对论原子结构软件包）计算能级和辐射率。为了确定碰撞强度和随后的激发速率，狄拉克原子R-矩阵代码（darc）被使用。振子强度，辐射率和线强度的所有E1，E2，M1和M2跃迁的最低49个级别的每个离子的报告。此外，列出了上述四种离子的所有49个能级的理论寿命。碰撞强度的平均超过麦克斯韦速度分布和有效的碰撞强度得到列出了在很宽的温度范围内高达107.5 K。与使用灵活的原子代码（fac）得到的类似数据进行比较，以突出共振的重要性，包括在计算与darc，在确定有效的碰撞强度。从darc和fac的碰撞强度之间的差异，特别是禁戒跃迁，也进行了讨论。最后，有效的碰撞强度与darc代码和早期的半相对论R-矩阵数据的本结果之间的差异，注意到在很宽的范围内的电子温度在所有离子的许多过渡。
We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in He-like Ti XXI, V XXII, Cr XXIII and Mn XXIV. grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates. For determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels of each ion. Additionally, theoretical lifetimes are listed for all the 49 levels of the above four ions. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 107.5 K. Comparisons are made with similar data obtained using the flexible atomic code (fac) to highlight the importance of resonances, included in calculations with darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, in particular for forbidden transitions, are also discussed. Finally, discrepancies between the present results for effective collision strengths with the darc code and earlier semi-relativistic R-matrix data are noted over a wide range of electron temperatures for many transitions in all ions.