Coronal lines and the importance of deep-core–valence correlation in Ag-like ions

Abstract

We report on large-scale and critically evaluated ab initio multiconfiguration Dirac-Hartree-Fock calculations of the wavelength and transition rate of the "coronal," M1 transition 4f 2 F o 5/2 -2 F o 7/2 in Ag-like ions. The transition between these two fine-structure levels, which makes up the ground term for Z 62 in the isoelectronic sequence, has recently been observed in Yb 23+ and W 27+ , where the latter could be of great importance for fusion plasma diagnostics. We present values for all members of the sequence between Z = 50 and 94, which are supported by excellent agreement with values from recent experiments. The importance of including core-valence correlation with the n = 3 shell in the theoretical model is emphasized. The results show close-to-spectroscopic accuracy for these forbidden lines.

Tungsten spectroscopy in the EUV range observed at a high-temperature superconducting electron-beam ion trap

“…Transition array 5 in the wavelength region of 174.8-176.8Å in the experimental spectra (see Fig. 2) is identified as belonging to the 4f 12 5s 2 5p5d → 4f 12 5s 2 5p 2 array, while the other two lines at 243.3 and 249.2Å are 5p → 5s transitions, outside a 4f 13 7/2 subshell. c. W 13+ .…”

“…In previous papers we have investigated visible M1 transitions in W 13+ [8], W 25+ [9], W 26+ [10], W 27+ [11] (with an extension to the silver isoelectronic sequence [12,13]), and W 28+ [14]. In the present work we report on a study of tungsten ions in the wavelength region of interest to ITER divertor diagnostics, i.e., 150-400Å.…”

“…Atomic structure calculations showed that the dominant emission arises from 5d → 5p and 5p → 5s transitions. The work also identified the ground-state configuration of W 13+ as 4f 13 …”

Resolving a discrepancy between experimental and theoretical lifetimes in atomic negative ions

“…A similar method was proposed and used for highly ionized species in what was labelled "single-line spectroscopy" for silverlike ions, e.g. Tungsten [23].…”

Energy levels and radiative data for Kr-like W38+from MCDHF and RMBPT calculations

“…Accurate and reliable atomic data on tungsten ions are therefore in high demand, which has initiated a large number of both experimental and theoretical investigations (see e.g. the reviews in [5][6][7][8] and some examples of recent works in [9][10][11][12][13][14][15][16][17][18][19][20]). …”