Energy spectra of collisionally producedH−autodetaching states

Abstract

Several lines, observed between 9 and 30 eV in the energy spectra of electrons ejected in 100-eV to 10-keV collisions of ${\mathrm{H}}^{-}$ with He, Ar, and ${\mathrm{H}}_2$, are attributed to autodetaching states of ${\mathrm{H}}^{-}$. The energy of the lowest line associated with the $\left(2\mathrm{}{s}^2\right){}_{}{}^1{}_{}{}^{}S$ state of ${\mathrm{H}}^{-}$ was found to be 9.59±0.03 eV. Two lines due to ${\mathrm{Ar}}^{-}$ autodetaching states were used to calibrate the energy scale. The separations in energy between the $\left(2\mathrm{}{s}^2\right){}_{}{}^1{}_{}{}^{}S$ line of ${\mathrm{H}}^{-}$ and several other lines lying below the $n=2\mathrm{}$ and $n=3\mathrm{}$ levels of hydrogen were measured. The present results agree well with theoretical predictions and with the experimentally observed resonances in the elastic scattering of electrons on atomic hydrogen.