The influence of ion gratings on rotational wavepacket dynamics in H2

We generalize earlier work [V.G. Stavros, E. Harel, S.R. Leone, J. Chem. Phys. 122 (2005) 064301] by illustrating the plausible role of ion gratings in time-dependent degenerate four-wave mixing (TD-DFWM) experiments in H2. We postulate that at high laser intensities (1014–1015 W/cm2), H 2 + /H+ ions generate a static ion grating, it’s signature manifested in the transformation from homodyne- to heterodyne-detection of the TD-DFWM signal, depending on laser intensity. The change in signal detection agrees with the calculated intensity for barrier suppression ionization (BSI) in H2 and the reported onset of saturation for H 2 + and H+, pointing towards the likely role of ion gratings in intense laser field, FWM experiments.