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 toΔN=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≤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 at a principal quantum number higher than that given by Mannervik et al.A Small relativistic effect is noticed at intrashell resonance.