Hybrid subconfiguration-average and level-to-level distorted-wave treatment of electron-impact single ionisation of W$^{15+}$ and W$^{16+}$

Abstract: Recently, we have demonstrated (Jin et al. 2020, J. Phys. B: At. Mol. Opt. Phys. 53, 075201) that a hybrid subconfiguration-average and level-to-level distorted wave treatment of electron-impact single ionisation (EISI) of W$^{14+}$ ions represents an accurate and manageable approach for the calculation of EISI cross sections of a complex ion. Here we demonstrate the more general validity of this approach by comparing hybrid cross sections for EISI of W$^{15+}$ and W$^{16+}$ with the recent experimental results of Schury et al. 2020, J. Phys. B: At. Mol. Opt. Phys. 53, 015201). Our calculations also account for the resonant-excitation double autoionisation (REDA) process which is important in the electron energy range 370-600 eV and for the possible presence of initially metastable ions in the experiment.