Electron-Ion Recombination Rate Coefficients and Photoionization Cross Sections for Astrophysically Abundant Elements. XII. Na IX, Na X, Mg X, and Mg XI for Ultraviolet and X-Ray Modeling

Relevant data is available at: http://www.astronomy.ohio-state.edu/~nahar/nahar_radiativeatomicdata/index.htmlDetailed study on the inverse processes of photoionization and electron-ion recombination for Na IX + hv ↔ Na X + e, Na X + hv ↔ Na XI + e, Mg X + hv ↔ Mg XI + e, and Mg XI + hv ↔ Mg XII + e is reported. The unified method for the total electron-ion recombination is used for the self-consistent results of total and level-specific recombination rate coefficients α_R and α_R(i) (subsuming both radiative recombination [RR] and dielectronic recombination [DR]), total recombination cross sections σ_RC, and total and partial level-specific photoionization cross sections σ_PI and σ_PI(g). The total recombination spectrum of cross sections and recombination rates versus photoelectron energy are presented for experimental applications. The unified method employs close-coupling approximation in the relativistic Breit-Pauli R-matrix (BPRM) method. The coupled channel wave function expansions for Li-like Na IX and Mg X consist of 17 core levels with excitations up to 3d orbital and for He-like Na X and Mg XI consist of 16 core levels of excitations up to 4f orbital, respectively. The results are presented for all fine-structure levels of the ions up to n ≤ 10, which correspond to 98 levels with 1/2 ≤ J ≤ 17/2 for Li-like Na IX and Mg X, 182 and 185 levels with 0 ≤ J ≤ 10 for He-like Na X and Mg XI, respectively. The level specific photoionization cross sections σ_PI(nSLJ) and recombination rates α_R(T; nSLJ) are obtained for the first time for these ions. The single-valued total α_R(T) is presented over an extended temperature range for astrophysical and laboratory plasma applications. The total unified α_R(T) for all ions agrees very well with the available published RR and DR rates. Total recombination rates for H-like Na XI and Mg XII are also presented for completeness. The results are expected to be accurate within 10%-15% from considerations of important atomic effects such as radiation damping, channel couplings, and interference of DR and RR. The comprehensive data sets are applicable for ionization balance and recombination-cascade models for UV and X-ray lines.This work was supported partially by the NASA Astrophysical Research and Analysis program