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

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