Elusive enhanced ionization structure for H2+ in intense ultrashort laser pulses

Enhanced ionization of H-2+ in intense ultrashort laser pulses was measured using molecular dissociation imaging of an H-2+ beam and with a pump-probe technique using cold target recoil ion momentum spectroscopy on a D-2 target. Both measurements show a broad, single-peak distribution for enhanced ionization, in contrast to the double-peak structure predicted by frozen nuclei theory. This calculated double-peak structure is most likely washed out by nuclear motion and to a lesser extent by intensity averaging.