Electron-helium double ionisation near the threshold: numerical investigations

The classical trajectory method is applied to the investigation of low-energy e+He to He 2+ +3e collisions. In contrast to the hydrogenic case numerical calculations appear unable to derive the ionisation threshold law by varying one or two initial parameters. Final electron energies appear as linear functions of the initial time parameter and it is conjectured that the energy distribution should be uniform within the total energy interval: 0.544