Half-collision model for multiple ionization by photon impact -: art. no. 042720

We present a simple half-collision model that allows the approximate calculation of absolute cross sections for multiple ionization by breaking this process down into a primary ionization event followed by a half-scattering event in which additional electrons are ionized. As a critical test for the feasability of this approach, we consider the double ionization of two-electron systems, which we describe in terms of the single ionization of the primary electron followed by impact ionization of the slow secondary electron. For triple ionization of lithium, the model decomposes the three-electron breakup process into a double ionization of the two inner electrons followed by electron-electron half-scattering of the receding electrons at the residual spectator 2s electron. We find surprisingly good agreement with recent experimental data.