Calculation of autoionization of He andH−using the projection-operator formalism

Improved calculations of the first several autoionization states of the lower symmetries (${}_{}{}^{1,3}{}_{}{}^{}S, {}_{}{}^{1,3}{}_{}{}^{}P_{}^o{}_{}{}^{}, {}_{}{}^{1,3}{}_{}{}^{}D_{}^e{}_{}{}^{}$) are reported. Unshifted energies are obtained by diagonalizing $\mathrm{QHQ}$ using a Hylleraas basis with more terms than used previously. Shifts, widths, and photoabsorption shape parameters $q$ (where appropriate) are obtained with the additional use of exchange approximate nonresonant continuum functions. Our previous calculations of ${\mathrm{H}}^{-}$ resonances are recapitulated and slightly augmented by using various improved nonresonant continua and correcting small previous errors. Comparison with other calculations and experiments is made. The latter is very satisfactory except for the lowest ${}_{}{}^1{}_{}{}^{}P$ autoionization state of He for which a more accurate experimental result is required.