Intense Laser Field Double Ionization And Dissociation Of Molecules In The Study

Using a semiclassicial rescattering model, we investigate the electron correlation in non-sequential double ionization (NSDI) process of diatomic molecules, which are aligned parallel and perpendicular to the intense linearly polarized filed, achieving insight into the molecular NSDI dynamics.It is shown that a simple hydrogen-molecule-like model can simulate nitrogen molecule effectively and also give the electron momentum correlation qualitatively and quantitatively consistent with experimental result. This indicates that the symmetry of the valence orbital (bonding symmetry) dominates the NSDI process of diatomic molecule in the present of laser field. A simple semiclassical model based on electron recollision picture is capable to reproduce qualitatively the experimental findings and provide a clear picture to the NSDI dynamics, and explain the intrinsical mechanism of NSDI of diatomic molecules. Our analysis also indicates that the NSDI mechanism is dependent on the alignment due to the dependence of the potential barrier on the alignment. Moreover, the shapes of the momentum distributions have close dependence on the laser intensity. Further work of arbitrary alignment molecular ensemble is under work.It is shown that in the non-sequential double ionization of D₂, as the laser varies from short to long wavelength, the returning electron's kinetic energy varies from below to above the ionization threshold of the parent ion, resulting in the dominance of collisional ionization at shorter laser wavelength and field-ionization at longer laser wavelength. We also calculate the double ionization time distribution of D2 and kinetic energy distribution of D+. The theoretical results are qualitatively consistent with the experimental measurements.