CAN HARMONIC-GENERATION CAUSE NONSEQUENTIAL IONIZATION

We use a simple two-electron model introduced previously in the litera ture (Watson et al 1997 Phys. Rev. Lett. 78 1884) to study the process of non-sequential double ionization of atoms. In particular, we discu ss the phenomena of non-sequential double ionization of helium and we show that there is a definite relationship between the dipole radiatio n of the outermost (strongly ionized) electron and the ionization of t he inner electron. We also investigate in detail the effect of quantum interference of the outer-electron wavefunction on the non-sequential ionization.