Resonant-excitation-double-autoionization process in the electron-impact ionization of Li-like ions

We have calculated the contributions of excitation-autoionization and resonant-excitation-double-autoionization indirect-ionization mechanisms to electron-impact ionization of Li-like B²⁺, C³⁺, N⁴⁺, O⁵⁺, and F⁶⁺ ions. We considered twelve autoionizing states arising from the 1s2s², 1s2s2p, 1s2p², 1s2s3s, and 1s2s3p configurations. Rydberg series 1s2s2ln'l' and 1s2s3ln'l' of resonances, which arise due to the resonant-excitation-double-autoionization process, are included in our calculation. The calculated resonance structures in the cross sections agree very well with recent crossed-beam measurements.