Electron-Ion Recombination Rate Coefficients, Photoionization Cross-Sections, and Ionization Fractions for Astrophysically Abundant Elements

A comprehensive and self-consistent set of new atomic data for photoionization cross sections, andpPI,total uniÐed recombination rate coefficients, of oxygen ions are obtained. The calculations area R (T), carried out in the close coupling approximation employing the R-matrix method. The uniÐed treatment of total recombination includes both the radiative and dielectronic processes. The analysis of astro-physical spectra and ionization balance requires atomic data for all ionization stages of an element, and the accuracy depends on the self-consistency and completeness of data. In the present work the criterion of self-consistency between the rates for the inverse processes of photoionization and recombination is satisÐed in an ab initio manner by employing an identical set of eigenfunction expansions in the calcu-lations for both atomic processes. State-speciÐc recombination rate coefficients are also presented for a large number of bound states. As a Ðrst application, the present are used to obtaina R (T) ionization fractions of oxygen ions in plasmas in coronal equilibrium. Ionization fractions in photo-ionization equilibrium can be readily obtained by employing the present data for the total and forpPI