Benchmarking Atomic Data from Large-scale Multiconfiguration Dirac–Hartree–Fock Calculations for Astrophysics: S-like Ions from Cr ix to Cu xiv

Abstract

We present a consistent set of calculated energies and E1, M1, E2, M2 radiative transition data for the main n=3 levels from the 3s 2 3p 4 , 3p 6 , s p d 3 3 3 4 configurations, producing the strongest lines, are found to be in good agreement, reaching spectroscopic accuracy, with the latest experimental values for Fe XI evaluated by Del Zanna. Our energies can reliably be used to identify in astrophysical and laboratory spectra the s p d 3 3 3 2 3 levels in other S-like ions, which are mostly unknown. On the contrary, significant discrepancies with the 3s3p 4 3d levels were found, emphasizing the need for more detailed experimental studies. A few new tentative identifications are suggested. The benchmarks we present indicate that our consistent set of radiative data is accurate and can be used for spectral line modeling.

Ab initio electronic factors of the A and B hyperfine structure constants for the 5s25p6s<

“…Yet, if one wants to be in a position to discuss atomic, or nuclear, properties and their underlying physics, a rigorous assessment of the uncertainties of the computed values is required. In recent years, atomic physicists have been putting great efforts into providing reliable uncertainties on their theoretical results [6,35,[69][70][71]. In line with these efforts, the following subsections take into account a number of considerations to determine the accuracy of the final B el [ 1 P o 1 ] value.…”

“…The uninterrupted developments of computational methodologies [1][2][3], together with the growing computational resources at the disposal of atomic physicists, have increased tremendously the accuracy of atomic structure calculations in the past decades [4][5][6][7][8][9][10][11]. Theoretical predictions of atomic properties have, therefore, become efficient tools to support the corresponding experimental measurements.…”

Benchmarking calculations with spectroscopic accuracy of excitation energies and wavelengths in sulfur-like tungsten

“…The RMBPT method [47][48][49] implemented in the FAC code [17] has been successfully used to calculate atomic data of high accuracy in our recent studies [31,[50][51][52][53][54][55][56][57][58][59][60]. In this method, a limited number of configurations can be included in the RCI expansion.…”

EUV Beam-Foil Spectra of Titanium, Iron, Nickel, and Copper

“…This complexity suggests that the present classifications [59] have to be considered as preliminary until better resolved data of higher statistical reliability and at further time steps become available, as well as accurate computations for all charge states expected. Recent ab initio computations (such as [32][33][34][36][37][38][39][40][41][42][43][44]114]) appear to be on the right path and reach an accuracy that is about an order of magnitude higher than what was available at the time of the beam-foil experiments described here. The measurement problem is further discussed below in the section on Ni.…”

“…Different approximations and computational approaches yield somewhat different results, resulting in a certain scatter among computational findings. Examples of recent computations on isoelectronic sequences that include ions of present interest (isoelectronic sequences F, Ne, Mg, Si, S) are [32][33][34][35][36][37][38][39][40][41][42][43] and references cited therein. Among the ab initio approaches with the most accurate results are Multireference Møller-Plesset computations of the Ishikawa group, MCDHF computations employing versions of the GRASP code, and RMBPT computations (for unfolding the akronyms and details of the approaches, see a recent review by Jönsson et al [44]).…”