Calculations of autodetachment lifetimes of metastable states of Ba$^-$ and Eu$^-$

The metastable $5d6s6p$ $J=9/2$ state of Ba$^-$, which decays by autodetachment to $6s^2\epsilon h$, has been found to be long lived with an estimated lifetime greater than 1 ms \footnote{ V. V. Petrunin $et~al.$, Phys. Rev. Lett. {\bf 75}, 1911 (1995).} \footnote{T. Andersen $et~al.$, J. Phys. B {\bf 30}, 3317 (1997).}. For the bound state, we have extended our basis set to include orbitals up to $l=6$ due to the importance of $\langle nlvl'|H|nl\epsilon h\rangle$ contributions to the energy width. We have also opened the $5p$ subshell to provide core-valence correlation to ensure proper mixing of the important $5d^2\epsilon h$ and $6p^2\epsilon h$ configurations in the continuum state. As we approach completion of this calculation, current results suggest an auto detachment lifetime greater than 10 ms. The analogous, and more computationally challenging, $4f^75d6s6p$ $J=8$ state in Eu$^-$, which decays by autodetachment to $4f^76s^2\epsilon h$, has been found to be similarly long lived.