Quasi-projection-operator calculation of autoionization states ofO5+(O VI) andSi11+(Si XII)

Inelastic quasi-projection-operator calculations of autoionization states of the three-electron ions of oxygen and silicon are carried out for states below the $n=3\mathrm{}$ manifold of the respective two-electron parent (i.e., ${\mathrm{O}}^{6+}$ and ${\mathrm{Si}}^{12+}$). Wave functions contain up to 40 configurations; calculations are completely ab initio. In the case of O VI calculated results agree with experimental results to within experimental error (∼ ±2 eV). For Si XII it is necessary to include relativistic effects; where formulas are available [states ($1s2s^{p}2p^q$) for which $p+q=2\mathrm{}$] our results are again in agreement with experiment for $2S^e,{}_{}{}^2{}_{}{}^{}P_{}^o{}_{}{}^{}$, and ${}_{}{}^2{}_{}{}^{}D_{}^e{}_{}{}^{}$ states. Our results for some of the higher states do not agree with tentative identifications proposed by Träbert et al.; alternative identifications are suggested.