Importance of radiation damping for low-lying photorecombination resonances

We have implemented a multi-channel quantum defect theory approach within the asymptotic R -matrix codes (STGF and STGBF) which treats all closed channels as open. Furthermore, making use of this approach, we have implemented an analytic preconvolution of undamped R -matrix photoionization and photorecombination cross sections. This removes any doubt whatsoever as to whether the resonances are fully resolved or not. We show that fully resolved undamped R -matrix photorecombination cross sections are in very close agreement with undamped perturbative cross sections. We demonstrate, with explicit examples, the large and widespread effect of radiation damping on low-lying photorecombination resonances for H-like through Ni-like ions. This refutes the recent claims made by Pradhan and Zhang and validates the original work of Robicheaux et al and Gorczyca and Badnell with regard to the importance of radiation damping.