Total electron-ion recombination of Fe III

It is shown that a method for calculating unified total electron-ion recombination rates, incorporating both the radiative and dielectronic recombination processes, can be applied to substantially complex atomic systems where a large number of recombination channels need to be coupled in an ab initio manner. Calculations are carried out for the astrophysically important ion Fe I I I, and total and state-specific recombination rate coefficients are obtained for e+ Fe I V → Fe I I I, in the close coupling approximation employing the R-matrix method. The calculations correspond to a 49-state eigenfunction expansion for the Fe I V core that includes states from the ground configuration 3${\mathit{d}}^5$ and the excited configurations 3${\mathit{d}}^4$4s and 3${\mathit{d}}^4$4p for proper treatment of the electron correlation effects. This is an accurate and detailed atomic calculation for the recombination rates for Fe I I I. The present rates are up to an order of magnitude lower than the previous values obtained through the Burgess general formula at electron temperatures where dielectronic recombination dominates. © 1996 The American Physical Society.