| Popis: |
Despite the tremendous advances in laser cooling of neutral atoms and positive ions, no negatively charged ion has been directly laser cooled. The negative ion of lanthanum, ${\mathrm{La}}^{--}$, has been proposed as the best candidate for laser cooling of any atomic anion [ and , Phys. Rev. A 81, 032503 (2010)]. Tunable infrared laser photodetachment spectroscopy is used to measure the bound-state structure of ${\mathrm{La}}^{--}$, revealing a spectrum of unprecedented richness with multiple bound-bound electric dipole transitions. The potential laser-cooling transition ($^{3}{F}_{2}^{e}\ensuremath{\rightarrow}^{3}{D}_{1}^{o}$) is identified and its excitation energy is measured. The results confirm that ${\mathrm{La}}^{--}$ is a very promising negative ion for laser-cooling applications. |
