Light-induced multiple electronic-state coupling of O2+ in intense laser fields

The dissociation processes, O2+→O++O, in intense laser fields (100 fs, ∼3×1014 W/cm2) are studied at the laser wavelength of 795 and 398 nm on the basis of the momentum imaging maps of the O+ fragment ions. The covariance map measurements are performed with high momentum resolution to assign securely the dissociation pathways. From the anisotropic momentum distribution of O+ with respect to the laser polarization direction, the electronic states of O2+ are found to be coupled exclusively through parallel transitions in the course of the dissociation process. The released kinetic energy of O+ for both 795 and 398 nm are interpreted consistently by a sequential coupling model of light-dressed potential curves of O2+ in the quartet Π state manifold.