Vibrationally resolved structure in O2+ dissociation induced by intense ultrashort laser pulses

Abstract

Laser-induced dissociation of O+ 2 is studied in the strong-?eld limit using two independent methods, namely a crossed laser-ion-beam coincidence 3D momentum imaging method and a supersonic gas jet velocity map imaging technique (790 and 395 nm, 8-40 fs, ~10 15 W/cm2 ). The measured kinetic energy release spectra from dissociation of O+ 2 and dissociative ionization of O2 reveal vibrational structure which persists over a wide range of laser intensities. The vibrational structure is similar for O+ 2 produced incoherently in an ion source and coherently by laser pulses. By evaluation of the potential energy curves, we assign the spectral energy peaks to dissociation of the v = 10-15 vibrational states of the metastable a 4 ??u state via the dissociation pathway |a 4 ??? ? |f 4 ??- 1??-a mechanism equivalent to bond softening in H+.