Allowed transitions and intercombination lines in C III and C II

Abstract

Systematic multiconfiguration Hartree-Fock results in the Breit-Pauli approximation are reported for the 2s2 1S0 → 2s2p 3P1 intercombination line in C III and the 2s22p2P-2s2p3 4P multiplet in C II. Length and velocity forms of the oscillator strengths of related allowed transitions are also reported. The latter are used as a check on accuracy along with term energy separation and spin-orbit splitting. The predicted transition rate of 103 ± 3 s−1 for the intercombination line in C III lies outside the experimental error bars whereas the decay rates for C II are near the lower experimental limits.