Multipole (E1, M1, E2, M2) transition wavelengths and rates between   states with n<= 6 in heliumlike carbon, nitrogen, oxygen, neon, silicon, and   argon
  Transition wavelengths and rates are given for E1, E2, M1, and M2 transitions between singlet and triplet S, P, D, and F states in heliumlike ions of astrophysical interest: carbon, nitrogen, oxygen, neon, silicon, and argon. All possible transitions between states with n <= 6 are considered. Wave functions and energies are calculated using the relativistic configuration-interaction (CI) method including both Coulomb and Breit interactions. For transitions to the ground state, the present theoretical wavelengths agree to five digits with precise measurements. 
I. M. Savukov, W. R. Johnson, and U. I. Safronova