Double ionization of argon by electron impact: use of the approximate 6C model

We study the electron impact double ionization of argon in the case where two, or else, three of the outgoing electrons (one scattered and two ejected) have the same energy. Each electron in the final (continuum) state is described by a Coulomb wave and account is taken for the interaction between these three electrons. We also include exactly all the exchange effects for the first time. The results of our model are compared to the recent experiments of Catoire et al (2004, Photonic, Electronic and Atomic Collisions ed R Schuch et al ( Phys. Scr. T110 228–32); 2005, Electron and Photon Impact Ionization and Related Topics ed B Piraux (Bristol: Institute of Physics) p 53).