  The influence of electron-electron Coulomb repulsion on nonsequential double
ionization of rare-gas atoms is investigated. Several variants of the
quantum-mechanical transition amplitude are evaluated that differ by the form
of the inelastic electron-ion rescattering and whether or not Coulomb repulsion
between the two electrons in the final state is included. For high laser
intensity, an entirely classical model is formulated that simulates the
rescattering scenario.
