Comparisons between perturbative and radiation-damped R-matrix approaches to dielectronic recombination: Application to Ar15+

We apply a recently formulated close-coupling technique [Robicheaux et al., Phys. Rev. A 52, 1319 (1995)], which includes radiation damping via an optical potential, to the calculation of dielectronic recombination cross sections of Ar15+. Specifically, we compare the results from both Wigner-Eisenbud and eigenchannel R-matrix calculations to perturbative methods. For this system, no evidence for interfering resonance phenomena is found, and excellent agreement is obtained among all methods. This indicates that the present close-coupling treatment of the dielectronic recombination is highly accurate and can therefore be used to investigate systems where lower-order perturbative methods are inappropriate, such as where interference effects between neighboring resonances and between direct and resonant recombination processes are expected.