Lamb-shift and fine-structure measurements inLi+7

We have measured the absolute wave numbers of the $2s{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-2p{}_{}{}^3{}_{}{}^{}P_J^{}{}_{}{}^{}$ transitions in ${}_{}{}^7{}_{}{}^{}\mathrm{Li}_{}^{+}{}_{}{}^{}$ by laser fluorescence spectroscopy on an ion beam. Using the hyperfine structure (hfs) theory of Jette, Lee, and Das, we have extracted the following hfs-free wave numbers: $\sigma (2s{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-2p{}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{})=18\mathrm{} 231.3030\left(12\right),\sigma (2s{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-2p{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{})=18\mathrm{} 226.1082\left(12\right)\mathrm{}$, and $\sigma (2s{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-2p{}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{})=18\mathrm{} 228.1979\left(12\right)\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$. By subtracting the theoretical values of Accad, Pekeris, and Schiff, we obtain the differential Lamb shifts $\mathcal{S}(2s{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-2p{}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{})=1.2539\mathrm{}\left(16\right),\mathcal{S}(2s{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-2p{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{})=1.2543\mathrm{}\left(16\right)\mathrm{}$, and $\mathcal{S}(2s{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-2p{}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{})=1.2545\mathrm{}\left(16\right)\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$. These results are in agreement with the calculations of Ermolaev and with earlier measurements by Bacis and Berry. The fine-structure intervals obtained from the absolute wave numbers are in agreement with the theory of Accad et al. and with the measurements of...