On the validity of the ICFT R-matrix method: Fe xiv
On the validity of the ICFT R-matrix method: Fe xiv
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DOI：
10.1093/mnras/stv2016
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发表时间：
2015-12
影响因子：
4.8
通讯作者：
G. Zanna;N. Badnell;L. Fernández-Menchero;G. Liang;H. Mason;P. Storey
中科院分区：
文献类型：
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作者：
G. Zanna;N. Badnell;L. Fernández-Menchero;G. Liang;H. Mason;P. Storey
最近，Aggarwal和Keenan发表了一个狄拉克R矩阵（darc）计算的电子碰撞激发的Fe xiv。采用136能级组态相互作用/紧耦合（CI/CC）展开。与Liang等人用中间耦合框架变换（ICFT）R矩阵方法获得的早期计算结果相比，显示出显著的差异。其中一个主要区别是Liang等人的有效碰撞强度始终较大。Aggarwal & Keenan提出了造成差异的各种可能原因。我们在这里详细讨论它们。我们用Aggarwal和Keenan采用的136层CI/CC展开进行了ICFT R矩阵计算，并将结果与他们的结果以及Liang等人的结果进行了比较，其采用了大得多的CI/CC扩展。我们发现，出现的主要差异，因为不同的CC和CI扩展，而不是因为使用的ICFT方法，建议由Aggarwal & Keenan。Liang等人获得的有效碰撞强度的显著增加主要是由于更大的目标膨胀而存在的额外共振。
Recently, Aggarwal & Keenan published a Dirac R-matrix (darc) calculation for the electron-impact excitation of Fe xiv. A 136-level configuration-interaction/close-coupling (CI/CC) expansion was adopted. Comparisons with earlier calculations, obtained by Liang et al. with the intermediate coupling frame transformation (ICFT) R-matrix method, showed significant discrepancies. One of the main differences was that the Liang et al. effective collision strengths were consistently larger. Aggarwal & Keenan suggested various possible causes for the differences. We discuss them in detail here. We have carried out an ICFT R-matrix calculation with the same 136-level CI/CC expansion adopted by Aggarwal & Keenan, and compared the results with theirs and with those of Liang et al., which employed a much larger CI/CC expansion. We find that the main differences arise because of the different CC and CI expansions, and not because of the use of the ICFT method, as suggested by Aggarwal & Keenan. The significant increase in the effective collision strengths obtained by Liang et al. is mainly due to the extra resonances that are present because of the larger target expansion.