Detailed discussion of discrepancy between theoretical and observed spectral lines in Kr-like W³⁸⁺ based on advanced consideration of core electron correlations

For the observed line at 799.23 Å in tungsten EBIT experiment, which was assigned to be ${}^3{\mathrm{F}}_4^{\mathrm{o}}-{}^3{\mathrm{F}}_3^{\mathrm{o}}$ (Ar4s²4p⁵4d) of W³⁸⁺ ion, there were noticeable deviations for most calculated wavelengths from the measured value. To clarify this issue, we carry out an extensive calculation for energy levels and transition properties of W³⁸⁺ ion using the multi-configuration Dirac–Hartree–Fock and relativistic configuration interaction method, in which more deeper inner core electron correlations are included, and different forms of Breit interaction as well as quantum electrodynamics corrections are investigated. It is found that the inner core electron correlations can affect the total energy of levels, while only slightly modify the excited energy of levels in 4s²4p⁵4d complex. The present calculated wavelengths agree with the corresponding measured values excellently except the line at 799.23 Å. Thus we are strongly suspicious this line should be misidentified, and suggest that new experiment with higher resolution and spectra analysis based on more accurate atomic data should be performed for W³⁸⁺ ion.