E1 transitions between states with n = 1 to 6 in helium-like carbon,   nitrogen, oxygen, neon, silicon, and argon
  Wavelengths and transition rates are given for E1 transitions between singlet S, P, D, and F states, between triplet S, P, and D states, and between triplet P and singlet S states in ions of astrophysical interest: helium-like carbon, nitrogen, oxygen, neon, silicon, and argon. All possible E1 transitions between states with J < 4 and n < 7 are considered. Energy levels and wave functions used in calculations of the transition rates are obtained from relativistic configuration-interaction calculations that include both Coulomb and Breit interactions. 
W. R. Johnson, I. M. Savukov, U. I. Safronova, and A. Dalgarno