Partial widths of theHe−2Stwo-electron ionization ladder resonances

We present results for the partial and total widths, with interchannel and intrachannel coupling included, of the 1s(nl${)}^2$ ${}_{}{}^2{}_{}{}^{}$S resonances of ${\mathrm{He}}^{\mathrm{-}}$, n=3 and 4. These are obtained by solving the corresponding state-specific complex eigenvalue Schrödinger equations and subsequently using simple formulas. A number of conclusions are drawn as to the wave-function characteristics and the distribution of the autoionization rates. The computations include the self-consistent interactions between the core and the valence electrons, localized valence correlations, and interactions among all the open channels with helium 1sNl ${}_{}{}^{3,1}{}_{}{}^{}$L, l=0,1,2 cores. These prototypical calculations can be carried out in larger systems as well, since the structure of the theory is such that it allows the quantitative treatments of multichannel dynamics in arbitrary polyelectronic atoms. For the total widths, comparison is made with a previous 19-state R-matrix calculation and with measurements.