Measurement of the self-energy contribution to the 2<i>s</i>-3<i>p</i>resonance transition in neonlike ytterbium

The self-energy contribution to the transition (2${\mathit{s}}_{1/2}$2${\mathit{p}}^{6}$3${\mathit{p}}_{3/2}$${)}_{\mathit{J}=1}$\ensuremath{\rightarrow}2${\mathit{s}}^{2}$2${\mathit{p}}^{6}$ in neonlike ${\mathrm{Yb}}^{60+}$ has been measured in an electron-beam ion trap to be 18.4\ifmmode\pm\else\textpm\fi{}0.8 eV. This value is 10% larger than the value obtained from multiconfiguration Dirac-Fock calculations in the commonly used effective-charge approach. The measurement supports earlier suggestions that the effective-charge approach may overcorrect the screening effect on the self-energy corrections for transitions in neonlike ions.