Alignment effect in nonsequential double ionization of diatomic molecules in strong laser fields

Abstract

Using a semiclassical rescattering model, we investigate the nonsequential double ionization (NSDI) process of diatomic molecules aligned parallel and perpendicular to the intense linearly polarized field. It is shown that a simple hydrogen-molecule-like model can simulate a nitrogen molecule effectively by giving the alignment dependence of the ratio of double to single ionization and the momentum distribution qualitatively consistent with the experimental result of ${\mathrm{N}}_{2}$. However, the alignment dependence of the momentum correlation of two ejected electrons does not agree with the experimental result, which indicates that the quantum effect needs to be included in the rescattering and the field-ionization process to explain the experimental observation.