Multiconfiguration Dirac-Fock calculations of the 2s²¹S₀–2s2p³P₁ intercombination transition in C III

Multiconfiguration Dirac-Fock calculations for the 2s²¹S₀–2s2p³P₁ intercombination transition in C III are revisited. To improve the accuracy, the orbital sets for the initial- and final-state wave functions were not restricted to be the same, but were optimized independently. The calculated 2s2p³P fine-structure splitting and the 2s²¹S₀–2s2p³P₁ transition energy are in good agreement with experiment. The predicted transition rate A=102.9±1.5s^-1 is in agreement with a recent storage-ring measurement by Doerfert et al. [Phys. Rev. Lett. 78, 4355 (1997)]. Results are also presented for the allowed 2s²¹S₀–2s2p¹P₁ transition and the 2s²¹S₀–2s2p³P₂ magnetic quadrupole transition.