ENERGY-LEVELS AND OSCILLATOR-STRENGTHS FOR TRANSITIONS IN HELIUM-LIKENI XXVII

Configuration interaction wavefunctions obtained using the CIV3 code a re used to calculate energy levels and oscillator strengths for all si gnificant electric dipole (E1), electric quadrupole (E2), magnetic dip ole (M1) and magnetic quadrupole (M2) transitions among the seventeen 1s2, 1s2l and 1s3l states of He-like Ni XXVII. Accurate wavefunctions are also obtained using the fully relativistic multi-configurational D irac-Fock (MCDF) method and similarly employed to calculate energy lev els and oscillator strengths. The derived energy levels are compared t o each other and also with previous results, and indicate that the MCD F method gives data which are closer to the experimental energies. Cal culated CIV3 and MCDF A-values are found to be in good agreement but t o differ significantly in some cases from those of previous authors.