Energy levels, radiative rates and electron impact excitation rates for transitions in Si XII, Si XIII and Si XIV
Energy levels, radiative rates and electron impact excitation rates for transitions in Si XII, Si XIII and Si XIV
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DOI：
10.1088/0031-8949/82/06/065302
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发表时间：
2010-12
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
在本文中，我们报告了Li-like Si XII， He-like Si XIII和H-like Si XIV跃迁的能级，辐射率和电子冲击激发率的计算。计算能级和辐射率时采用的是grasp（通用相对论原子结构包），而确定碰撞强度和激发率时使用的是Dirac原子r矩阵代码（darc）。在Si XII最低的24个能级、Si XIII最低的49个能级和Si XIV最低的25个能级中，报告了所有E1、E2、M1和M2跃迁的振荡器强度、辐射率和线强度，属于n≤5个构型。碰撞强度在麦克斯韦电子速度分布上得到了平均，并在107 K以下的宽温度范围内得到了有效碰撞强度。与从柔性原子代码（facc）获得的类似数据进行了比较，以突出darc计算中包含的共振在确定有效碰撞强度方面的重要性。本文还讨论了darc和face碰撞强度的差异，特别是在弱跃迁和低能时。此外，尽管没有可用的测量值来比较，但仍列出了上述三种离子的所有计算水平的寿命。
In this paper, we report calculations of energy levels, radiative rates and electron impact excitation rates for transitions in Li-like Si XII, He-like Si XIII and H-like Si XIV. The grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates, while 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 24 levels of Si XII, 49 levels of Si XIII and 25 levels of Si XIV, belonging to the n≤5 configurations. Collision strengths have been averaged over a Maxwellian electron velocity distribution and the effective collision strengths so obtained are reported over a wide temperature range below 107 K. Comparisons have been made with similar data obtained from the flexible atomic code (fac) to highlight the importance of resonances, included in calculations from darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, particularly for weak transitions and at low energies, are also discussed. Additionally, lifetimes are listed for all calculated levels of the above three ions, although no measurements are available with which to compare.