Energy levels, radiative rates and electron impact excitation rates for transitions in C iii
Energy levels, radiative rates and electron impact excitation rates for transitions in C iii
复制标题
C iii 跃迁的能级、辐射速率和电子碰撞激发速率
DOI：
10.1093/mnras/stv684
复制
发表时间：
2015
影响因子：
4.8
通讯作者：
Aggarwal K
中科院分区：
文献类型：
--
作者：
Aggarwal K
我们报告的能量水平，辐射率（a值）和寿命的天体物理重要的类贝离子Ciii。计算时考虑166个能级，属于≤5个构型，采用通用相对论原子结构包（General-purpose relativity Atomic Structure Package）。所有E1， E2， M1和M2跃迁都提供了爱因斯坦系数，而寿命与现有测量和理论结果进行了比较，没有发现大的差异。我们的能量水平被评估为精确到大多数水平的1%以上，而a值在大多数转换中优于20%。还计算了碰撞强度，其中使用了Dirac AtomicR-matrix Code （darc）。考虑了高达21里德的宽能量范围，并在阈值区域的精细能量网格中解析共振。碰撞强度随后在麦克斯韦速度分布上平均，以确定8.0 × 105K温度下的有效碰撞强度，足以用于大多数天体物理应用。我们的数据与Fernández-Menchero等人最近的center矩阵计算进行了比较，在结果的整个温度范围内的几个转变中注意到显着差异（高达一个数量级以上）。
We report energy levels, radiative rates (A-values) and lifetimes for the astrophysically important Be-like ion Ciii. For the calculations, 166 levels belonging to then≤ 5 configurations are considered and thegrasp(General-purpose Relativistic Atomic Structure Package) is adopted. EinsteinA-coefficients are provided for all E1, E2, M1 and M2 transitions, while lifetimes are compared with available measurements as well as theoretical results, and no large discrepancies noted. Our energy levels are assessed to be accurate to better than 1 per cent for a majority of levels, andA-values to better than 20 per cent for most transitions. Collision strengths are also calculated, for which the Dirac AtomicR-matrix Code (darc) is used. A wide energy range, up to 21 Ryd, is considered and resonances resolved in a fine energy mesh in the thresholds region. The collision strengths are subsequently averaged over a Maxwellian velocity distribution to determine effective collision strengths up to a temperature of 8.0 × 105K, sufficient for most astrophysical applications. Our data are compared with the recentR-matrix calculations of Fernández-Menchero et al., and significant differences (up to over an order of magnitude) are noted for several transitions over the complete temperature range of the results.