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

Abstract

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 ∼10% at temperatures where an ion is predicted to form in collisional ionization equilibrium and up 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.

A Decade with VAMDC: Results and Ambitions

“…The Photonic Electronic Atomic Reaction Laboratory (PEARL) database in the Korea Atomic Energy Research Institute (KAERI) includes electron impact ionisation (EII), recombination and photoionisation for atoms and ions. The EII [141] and the dielectronic recombination (DR) [142] have been calculated using a relativistic distorted wave approximation, and the photoionisation [143] has been calculated using a non-iterative eigenchannel R-matrix method for the ground and lower excited levels of atomic ions below Z = 30, which are of interest in astrophysics. The EII [144] and the DR [145] calculations have also been performed for tungsten (W, Z = 74) ions, which are essential in fusion tokamak research.…”