Role of e-e repulsion interaction in nonsequential double ionization of Xe by linearly and elliptically polarized laser pulses

We investigated the nonsequential double ionization (NSDI) of Xe by linearly polarized (LP) and elliptically polarized (EP) laser pulses using the classical ensemble model. For the two cases, the ensemble from NSDI was separated into two kinds of subensemble according to the relative momentum along the y-axis (k1/12), respectively. The results show only for the case of relatively small k1/12, the momentum distribution along the x-axis can show a V-like shape obviously, which is according with the experiment [Phys. Rev. Lett. 99, 263003 (2007)]. What is important is that we firstly examine the role of the repulsion interaction between two electrons for the two kinds of subensemble, and find that the process of NSDI for the case of relatively small k1/12 exits a strong repulsion interaction which contributes significantly to the V-like shape. However, for the case of relatively big k1/12, the repulsion interaction between two electrons is relatively weak, and both the nuclear Coulomb attraction and electric field force dominate the process of NSDI.