Oscillator strengths forS-PandP-Dtransitions in heliumlike ions

Explicitly correlated wave functions are constructed for the ${}_{}{}^1{}_{}{}^{}\mathrm{S}$, n ${}_{}{}^3{}_{}{}^{}\mathrm{S}$, n ${}_{}{}^1{}_{}{}^{}\mathrm{P}$, n ${}_{}{}^3{}_{}{}^{}\mathrm{P}$, ${}_{}{}^1{}_{}{}^{}\mathrm{D}$, and n ${}_{}{}^3{}_{}{}^{}\mathrm{D}$ states, with n<7, of the two-electron ions from He through ${\mathrm{Ne}}^{8+}$. 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.