Relativistic calculation of dielectronic recombination on the C4+ ground state

The relativistic multichannel theory has been applied and a nonperturbative formula adopted to calculate the dielectronic recombination cross section due to DeltaN = 1 resonances for the ground state C4+. The first-order approximation is adopted for the radiative process and a correction based on the isolated resonance approximation is used for the very narrow resonances to include the radiation width. The convoluted cross section is in agreement within 5% with, that of observation for resonances with n less than or equal to 5. For n = 6 and 7, the integral cross section is overestimated by a factor of 6 and 4, respectively. According to our calculation, the Rydberg cut-off due to field ionization should be st a principal quantum number higher than that given by Mannervik et al. A small relativistic effect is noticed at intrashell resonance.