Polarization effects on nonsequential double ionization of molecular fragments in strong laser fields

In this paper, we study nonsequential double ionization in various molecular fragments for laser polarization aligning either parallel or perpendicular to the molecular axis. In the diatomic molecule O2, we find that nonsequential double ionization can be turned on and off when we simply switch the laser polarization between perpendicular and parallel ionization. Furthermore, we find that the dependence of kinetic energy release on intensity can be used to distinguish sequential versus nonsequential ionization in molecules. The results in this paper allow us to gain better understanding of the role of nonsequential ionization in molecular dissociative ionization.