OSCILLATOR-STRENGTHS FOR S-P AND P-D TRANSITIONS IN HELIUM-LIKE IONS

Explicitly correlated wave functions are constructed for the n 1S, n 3S, n 1P, n 3P,n 1D, and n 3D states, with n < 7, of the two-electron ions from He through Ne8+. The variational energies are the best available for 180 of the 261 states. Electron-nuclear and electron-electron cusp checks are used to test the wave functions. For each ion, dipole oscillator strengths are calculated for 55 S-P and 40 P-D transitions. Our oscillator strengths are more accurate than previous values for 739 of the 855 transitions considered. Some coefficients for the 1/Z expansions of the energies and oscillator strengths have been estimated as an aid to extrapolating our results to higher nuclear charges.