Breakup of H2+ by one photon in the presence of a strong dc field -: art. no. 053404

We calculate the frequency profile of the rate for breakup of H-2(+) by one photon in the presence of a strong dc field. After photoexcitation of the molecular ion from its ground 1s sigma electronic state to the 2p sigma electronic state, the nuclei are temporarily trapped by a dc field-induced barrier with turning point R-max. However, the nuclei are released through either rotation of the internuclear axis (which, for the sake of tractability, we ignore) or dc-field ionization involving resonant transfer from the 2p sigma state to a more highly excited state. The most prominent resonance occurs at an internuclear separation that is less than R-max and, in a.u., is approximately 3/(8F(dc))+3, where F-dc is the dc field strength. We interpret the change in the frequency profile, as F-dc varies, in terms of different aspects of the dynamics of the breakup process, in particular the dispersion of the probability distribution of the nuclei due to over-the-barrier dissociation from the 1s sigma state.