Electron-impact double ionization of He by applying the Jacobi matrix approach to the Faddeev-Merkuriev equations

We apply the Jacobi matrix method to the Faddeev-Merkuriev differential\n equations in order to calculate the three-body wave function that\n describes the double continuum of an atomic two-electron system. This\n function is used to evaluate within the first-order Born approximation,\n the fully differential cross sections for (e, 3e) processes in helium.\n The calculations are performed in the case of a coplanar geometry in\n which the incident electron is fast and both ejected electrons are slow.\n Quite unexpectedly, the results obtained by reducing our\n double-continuum wave function to its asymptotic expression are in\n satisfactory agreement with all the experimental data of Lahmam-Bennani\n et al. [A. Lahaman-Bennani et al., Phys. Rev. A 59, 3548 (1999); A.\n Kheifets et al., J. Phys. B 32, 5047 (1999).] without any need for\n renormalizing the data. When the full double-continuum wave function is\n used, the agreement of the results with the experimental data improves\n significantly. However, a detailed analysis of the calculations shows\n that full convergence in terms of the basis size is not reached. This\n point is discussed in detail.