Electron-ion recombination of FetII

Abstract

A complete treatment of electron-ion recombination of e+Fe III\ensuremath{\rightarrow}Fe II employing a unified method is presented. The treatment incorporates both the radiative and dielectronic recombinations in a self-consistent manner. Total recombination rate coefficients are obtained from photoionization cross sections, and from collision strengths for dielectronic recombination calculated using the precise theory of Bell and Seaton [J. Phys. B 18, 1589 (1985)]. Large-scale computations for both of these quantities are carried out in the close coupling approximation using the R-matrix method with an eigenfunction expansion that includes 83 states of Fe III dominated by the ground ${3\mathrm{d}}^{6}$, and the excited ${3\mathrm{d}}^{5}$4s and ${3\mathrm{d}}^{5}$4p configurations. Both the total and state-specific recombination rate coefficients are obtained. Comparison of the present results with the previous ones shows considerable difference for most of the temperature regions. The present results provide accurate and self-consistent recombination rates, in the temperature range of practical applications (T${10}^{5}$ K), for ionization balance in photoionization models employing the detailed photoionization cross sections from the Opacity Project.