ELECTRON-IMPACT IONIZATION OF TITANIUM IONS

In an animated crossed-beams experiment the following absolute cross s ections sigma(q,q+n) for single (n = 1), double (n = 2), triple (n = 3 ) and quadruple (n = 4) ionization have been measured for the reaction e + Tiq+ --> Ti(q+n+) + (n + 1)e sigma(5,6) (n = 1); sigma(2,4) (n = 2); sigma(2,5) (n = 3); sigma(2,6) (n = 4). The measurements have been performed in an energy range from threshold up to 1 keV, partly to 6 keV. The cross section for single ionization of ions in charge state q = 5 shows both contributions below the ground state threshold caused by the ionization of ions in excited, metastable states in the parent ion beam as well as from excitation-autoionization processes. The cros s section is described well by distorted-wave calculations. The cross sections for multiple ionization show considerable contributions from inner shell processes. Semiempirical formulae are in reasonable agreem ent with the experimental data.