Dielectronic recombination rate coefficients to the excited states of CIII from CIV

Energy levels, radiative transition probabilities and autoionization rates for CIII including 1s22pnl′ [n = 2–6, l′ ≤ (n − 1)] and 1s23lnl′ [n = 3–6, l′ ≤ (n − 1)] states were calculated by using the multi-configurational Hartree-Fock method (Cowan code). Autoionizing levels above the 1s22s and 1s22p thresholds were considered and their contributions were computed. Branching ratios on the autoionization rate to the first threshold and intensity factors were calculated for satellite lines of the CIII ion. The dielectronic recombination rate coefficients to the excited states for n = 2–6 were calculated. The values for the excited states higher than n = 6 were extrapolated and the total dielectronic recombination rate coefficients were derived. The rate coefficients to the excited states were fitted to an analytical formula and the fit parameters are given.