Laser Spectroscopy of Metastable Extreme-Ultraviolet Levels in Lithium Atoms and Ions

Abstract

An experiment is reported in which an intense laser is used to cause the intercombination transfer of metastable $1s2s2p{}_{}{}^4{}_{}{}^{}P_{\frac{5}{2}}^{}{}_{}{}^{}$ atoms to the $1s2p^2{}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ level with subsequent radiation in the extreme ultraviolet, thereby providing the first direct tie between the quartet and doublet manifolds in neutral Li. Intercombination transfer between the triplet and singlet manifolds of ${\mathrm{Li}}^{+}$ and tunable anti-Stokes radiation centered near 199 Å are also described.