Resolution of the Long-Standing Overprediction of the Resonance to Intercombination Line-Intensity Ratio in mid-Z Neonlike Ions
The Ne-like resonance 2p{sup 6} {sup 1}S-2p{sup 5}3d{sup 1}P(3C) to intercombination 2p{sup 6} {sup 1}S-2p{sup 5}3d{sup 1}D(3D) line-intensity ratio R(3C/3D) has been extensively studied through high-accuracy measurements and calculations of atomic structure and collision cross sections. However, even state-of-the-art relativistic multiconfiguration atomic-physics codes generally predict values of R(3C/3D) that are significantly larger than those observed in coronal-density experiments. In this paper, predictions of R(3C/3D) across the Ne-like isoelectronic sequence from chromium to silver are brought into agreement with coronal-density experimental measurements in two steps: first by including a semi-empirical correction in the collisional atomic data due to configuration-interaction effects, and next by including the effects of cascades on the upper level populations. The configuration-interaction correction is inspired by the observation that nearly all data-production codes fail to predict R(3C/3D) correctly and is justified theoretically by a careful analysis of configuration-interaction contributions to level energies. The dependence of R(3C/3D) with electron density and its agreement with moderate-density measurements are shown. A brief description of the application of our technique to line ratios in He- and Ni-like x-ray spectra is also given.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15014636
- Report Number(s):
- UCRL-JRNL-205066; PLRAAN; TRN: US0800896
- Journal Information:
- Physical Review A - Atomic, Molecular, and Optical Physics, Vol. 71, Issue 1; ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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