Photoionization cross sections and radiative recombination rate coefficients for positive ions of carbon and gold

Abstract

Partial photoionization cross sections based on a nonhydrogenic single-electron model that utilizes Dirac--Slater wave functions and all necessary multipoles have been computed for C III-VI and Au + 8, +16, +24, and +36 for n = 1 - 6 and 10, 0 less than or equal to l < n. By use of detailed balance, radiative recombination rate coefficients are obtained for seven temperatures in the range 10 eV - 3 keV from the photoionization cross sections. The cross sections are compared with those obtained by others using semiclassical (Kramers) and hydrogenic models. In most cases, the recombination rate coefficients (summed over subshells) are larger than those computed using hydrogenic photoionization cross sections, by as much as a factor 30 (Au + 8, n = 5, kT = 43 keV). Analytical fits are given for the rate coefficients summed over l and n. The results are applicable to ionization balance and ion transport calculations for fusion reactors and the solar corona.