Indirect processes in electron-impact ionization of Li+

The first detailed result is reported for the contribution of indirect proc esses in electron-impact ionization of Li+ ions in the energy range 132-168 eV using a unified theoretical treatment based on the R-matrix method. Ele ven bound target states, ten pseudo states, together with 26 autoionizing s lates, a total of 47 stales, are explicitly included in the R-matrix expans ion to describe both direct and indirect processes as well as interaction b etween them. The calculated resonance features due to double-excitation aut oionization, resonant double-excitation double-autoionization and resonant double-excitation auto-double-ionization are in very good agreement with th e experimental results of Muller et al (Muller A et nl 1989 Phys. Rev. Lett . 63 758).