The influence of ion gratings on rotational wavepacket dynamics in H2

Abstract

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), H2+/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 H2+ and H+, pointing towards the likely role of ion gratings in intense laser field, FWM experiments. © 2007 Elsevier B.V. All rights reserved.