Bound excited states of ${\mathrm{H}}^{-}$ and ${\mathrm{He}}^{-}$ in the statically screened Coulomb potential

The stability of the bound excited states of both the hydrogen and helium anions in an environment represented by the statically screened Coulomb potential have been studied. Energies have been calculated at the full configuration interaction level of theory, as a function of the screening parameter. Our calculations demonstrate that the bound excited states of both ${\mathrm{H}}^{-}$ and ${\mathrm{He}}^{-}$ survive only under mild screening conditions. Stronger screening will yield a sequential electron detachment process. Finally, the applicability of the present calculations to model real plasmas is discussed.