Intermediate-coupling calculations for the dielectronic recombination of B-like ions

Abstract

We have calculated Δn=0 dielectronic recombination cross sections and rate coefficients for the B-like ions ${\mathrm{C}}^{+}$, ${\mathrm{N}}^{2+}$, ${\mathrm{O}}^{3+}$, and ${\mathrm{F}}^{4+}$ in the LS-coupling and intermediate-coupling approximations, using the program a u t o s t r u c t u r e, as well as in a partitioned configuration-average approximation (PCA). There is broad agreement between the zero-field PCA results and the LS-coupling and intermediate-coupling results, which differ by no more than 10%. The experimental cross sections obtained by Dittner et al. lie between the zero-field and the maximum-field-enhanced PCA results, the enhancement being a factor of 3. In the case of the rate coefficients the general formula of Burgess was found to overestimate the zero-field results by a factor of between 1.3 and 1.8, mainly due to the neglect of autoionization into excited states.