EFFECTS OF CONFIGURATION INTERACTION FOR DIELECTRONIC RECOMBINATION OF Na-LIKE IONS FORMING Mg-LIKE IONS

Theoretical dielectronic recombination (DR) rate coefficient calculations can be sensitive to configuration interaction (CI) between resonances with different captured electron principle quantum numbers n. Here we explore the importance of this multi-n CI process for DR via 2l -> 3l' core excitations and its effect on the total DR rate coefficient. Results are presented for selected Na-like ions from Ca(9+) to Zn(19+). We find that including this multi-n CI can reduce the DR rate coefficient by up to similar to 10% at temperatures where an ion is predicted to form in collisional ionization equilibrium and up to similar to 15% at higher temperatures. To a first approximation, this will translate into a corresponding increase in the ion abundance. Charge state distributions calculation seeking to be accurate to better than 10% will thus need to take this effect into account. We also present simple fits to the calculated rate coefficients for ease of incorporation into plasma models.