Experimental wavelengths for intrashell transitions in tungsten ions with partially filled $3p$ and $3d$ subshells

Spectra and measured wavelengths of intrashell $n=3$ transitions in highly charged tungsten ions with partially filled $3p$ and $3d$ valence shells, Al-like W${}^{61+}$ through Fe-like W${}^{48+}$, are presented. The ions were created and excited at the electron-beam ion-trap facility at the Lawrence Livermore National Laboratory and measured with a high-resolution grazing-incidence spectrometer. The spectral lines were studied in the 27–41 Å range and were analyzed by a comparison with synthetic spectra based on a collisional-radiative model. We determined that the emission includes not only electric-dipole-allowed transitions, but also several electric-quadrupole and magnetic-dipole transitions. Line-position uncertainties as low as 25 ppm were achieved. Thus, our measurements provide much-needed benchmarks for calculations of the atomic structure of highly charged ions with a partially filled subshell, since these ions are difficult to calculate due to electron-correlation effects.

Figure 1

EBIT-I spectrum of highly charged tungsten recorded in the 26.5–35.0 Å range at a beam energy of 18.2 keV.

Figure 2

EBIT-I spectrum of highly charged tungsten recorded in the 33.0–43.5 Å range at a beam energy of 18.2 keV.