An Effective Eigenchannel R-Matrix Method for Calculating Electron-Ion Scattering Processes with Spectroscopic Precision

The electron-ion scattering processes are very important in various scientific research fields such as astrophysical studies and inertial confinement fusion research. We report our recent development of an efficient method for providing such atomic data with spectroscopic precision. Based on the Breit–Pauli and the Dirac R-matrix theory, we develop two eigenchannel R-matrix codes, referred to as R-eigen (non-relelativistic eigenchannel R-matrix) and R-R-eigen (relativistic eigenchannel R-matrix), to directly calculate the physical quantities in multichannel quantum defect theory in the whole energy regions. From such physical quantities, we can obtain all energy levels and the related scattering cross sections with accuracies comparable with spectroscopic precision. The e+Kr⁺ system is used as an illustration example, the degrees of accuracies of scattering matrices are calculated within about 2%, which should be much more accurate than state-of-the-art scattering experiments.