D1 and D2 lines in $^{6,7}$Li including QED effects

Abstract

Accurate theoretical predictions including leading QED corrections for $2^2P_{1/2} - 2^2S_{1/2}$ (D1) and $2^2P_{3/2} - 2^2S_{1/2}$ (D2) transition energies have been obtained for $^{6,7}$Li isotopes. Our results for the Bethe logarithms $\ln k_0(2^2S) = 5.178\,169(4)$, and for mass polarization corrections $\Delta \ln k_0(2^2S) = 0.113\,81(3)$ are in disagreement with ones obtained recently in the literature. In contrast, results $\ln k_0(2^2P) = 5.179\,81(7)$ and $\Delta \ln k_0(2^2P) = 0.111\,3(5)$ are in good agreement with them. From our theoretical predictions and recent measurements of $^{6,7}$Li D-lines at NIST, we determine the mean square charge radius difference between $^7$Li and $^6$Li nuclei, in agreement with determinations based on the $3^2S_{1/2}-2^2S_{1/2}$ transition, what demonstrates consistency of atomic spectroscopy determination of fundamental properties of nuclei.