Target wavefunctions in electron scattering from helium-like ions

Target wavefunctions in calculations of ionization cross sections of helium-like ions by electron impact are obtained by using the variational method. Wavefunctions for twenty-five states in N5+, O6+ and Ne8+ are represented with configuration interactions. Twelve orthogonal orbitals are used in the calculation, five spectroscopic (1s, 2s, 2p, 3s, 3p, 3d) and seven pseudo-orbitals, the later being included to allow for additional correlations. Present values for excitation energies are in good agreement with experimental results. (author)