Ionization potentials, radiative corrections and singlet-triplet corrections in the ground, n¹,³S and n¹,³P states of two-electron ions

Non-relativistic potentials, mass polarization corrections and relativistic contributions of order alpha 2 ry are obtained theoretically for the n 1,3 S and the n 1,3 P(n<or=5) states of all two-electron ions with Z in the range 11<or=Z<or=42. Radiative (QED) corrections of order alpha 3 ry are estimated for the ground and n 1,3 S, n 1,3 P(n=2,3) states throughout the range 4<or=Z<or=42. Estimates for the singlet-triplet corrections to the n 1,3 P 1 potentials (n<or=5) and of the corresponding singlet-triplet mixing coefficients were made in the range 3<or=Z<or=42. For completeness, all these quantities have been tabulated over the entire range 2<or=Z<or=42. In addition the fine structure intervals and interval ratios in the n 3 P states have been tabulated in this range. The accuracies of the ionization potentials and all the various corrections are specified. Some applications of the results are discussed.