A review of large-scale atomic calculations using the R-matrix method will be presented under the auspices of the IRON Project (IP) and the RmaX Project. The IRON project is focused on collisional and radiative calculations primarily for the iron-peak elements. In particular, collisional excitation cross sections and rate coefficients have been computed for all iron ions. The RmaX Project is aimed at ions of interest in X-ray astronomy and laboratory plasmas. The two projects entail major atomic processes of interest in astrophysical and laboratory sources: photoionization, electron-ion recombination, electron impact excitation, and radiative transition probabilities. Relativistic effects are included using the Breit-Pauli R-matrix (BPRM) method.
A comparison of the IP and RmaX Close-Coupling results with other simpler approximations shows large differences. The nature of the IP and the RmaX projects is characterized by the many atomic levels included in the total wavefunction expansions that enable (A) high accuracy, (B) extended energy ranges, and (C) large-scale producation of atomic datasets.
Among the recent results are extensive radiative (photoionization and bound-bound transitions) and collisional calculations for Ne-like Fe XVII, which is a prominent constituent of many X-ray sources. A 89-level BPRM calculation for electron scattering, are benchmarked against two different experimental measurements. A 60-level photoionization and recombination calculations for (hnu + Fe XVII) <---> (e + Fe XVIII) is compared with previous 3-level calculations. The results exemplify phenomena of general importance.
The Coupled-Channel R-matrix method enables self-consistent results for the inverse processes of photoionization and (e + ion) recombination, subsuming both radiative and dielectronic recombination (RR + DR) in a unified manner, using the same wavefunction expansion (Nahar and Pradhan, review in Radiation Processes in Physics and Chemistry , 70, 323, Elsevier, 2004).