Multiple ionisation of multiply charged xenon ions by electron impact

Abstract

Electron-ion crossed beams have been employed to obtain absolute cross sections for double ionisation of Xe^q+ ions (q=1, 2, 3, 4), threefold ionisation of Xe^q+ ions (q=1, 2, 3) and fourfold ionisation of Xe¹⁺ and Xe²⁺ ions by impact of a single electron with an energy up to 700 eV. Extremely large cross sections have been found showing that multiple ionisation of a complex ion can be as important as single ionisation. The relative strengths of multiple versus single ionisation are investigated as a function of ion charge state, ion atomic number and electron energy. Contributions of inner-shell ionisation are identified.