Measurement of the self-energy contribution to the 2s-3presonance 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}$ ${)}_{\mathit{J}=1\mathrm{}}$→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±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.