Extended Calculations of Spectroscopic Data: Energy Levels, Lifetimes, and Transition Rates for O-like Ions from Cr xvii to Zn xxiii

Abstract

Employing two state-of-the-art methods, multiconfiguration Dirac-Hartree-Fock and second-order many-body perturbation theory, the excitation energies and lifetimes for the lowest 200 states of the 2s 2 2p 4 , 2s2p 5 , 2p 6 , 2s 2 2p 3 3s, 2s 2 2p 3 3p, 2s 2 2p 3 3d, 2s2p 4 3s, 2s2p 4 3p, and 2s2p 4 3d configurations, and multipole (electric dipole (E1), magnetic dipole (M1), and electric quadrupole (E2)) transition rates, line strengths, and oscillator strengths among these states are calculated for each O-like ion from Cr XVII to Zn XXIII. Our two data sets are compared with the NIST and CHIANTI compiled values, and previous calculations. The data are accurate enough for identification and deblending of new emission lines from the sun and other astrophysical sources. The amount of data of high accuracy is significantly increased for the n = 3 states of several O-like ions of astrophysics interest, where experimental data are very scarce.

Solar UV and X-ray spectral diagnostics

“…These calculations have recently been extended to include many levels, for ions from Cr xvii to Zn xxiii by Wang et al. (2017). Rynkun et al.…”

Multiconfiguration Dirac-Hartree-Fock Calculations with Spectroscopic Accuracy: Applications to Astrophysics

“…Wang and co-workers have systematically compared large sets of transition rates from accurate RMCDHF/RCI and RMBPT calculations [49][50][51][52]. These comparisons show that the rates from the two methods agree within a few percent for the strong transitions and that the agreement gets slightly worse for the weak intercombination and the two-electron, one photon transitions 1 .…”

“…To meet this demand, the RMCDHF/RCI and SD-MR calculations for the B-, C-, N-, O-, F-and Ne-like sequences have been extended to hundreds of states in what we refer to as spectrum calculations [45][46][47][48][49][50][51][52]. The range of ions, the targeted configurations and the number of studied states for each sequence are summarized in Table 5.…”

“…The reason for this shift is not known, and further research is needed to shed light on this. To further access the accuracy of the excitation energies, calculations for the N-, O-, F-and Ne-like sequences [49][50][51][52] were done using both the RMCDHF/RCI and RMBPT methods. Cross-validations show that the mean energy differences for N-like, O-like, F-like and Ne-like Fe are 0.023%, 0.011%, 0.01% and 0.029%, respectively.…”

“…The RMCDHF/RCI and SD-MR method has been used to compute tens of thousands of E1, M1, E2, M2 transitions rates for the B-to Si-like sequences [28][29][30][31][32]43,[45][46][47][48][49][50][51][52][54][55][56]. The E1 and E2 rates are internally validated by giving δA/A along with A.…”