LIED:: laser induced electron diffraction by intense laser-molecule interaction -: an exact non-Born-Oppenheimer simulation of the one-electron system:: H2+

Exact non-Born-Oppenheimer simulations of a 1-D model of H-2(+) in an intense short laser pulse are used to investigate the non-linear multiphoton electron emission spectra, also called above-threshold ionization (ATI) spectra. Due to the fast proton motion upon dissociative-ionization, the electron ATI spectra are found to occur at the critical distance R-c similar or equal to 7 a.u. by charge resonance enhanced ionization, CREI. Highly oscillatory ATI spectra occur, which are enhanced by the molecular motion, and these are the signature of incomplete localization of the electron by the laser field. It is suggested that re-scattering effects result in doubling of the ATI intensity oscillations with respect to simple coherent excitation models of the HOMO and LUMO in H-2(+). (C) 2002 Elsevier Science B.V. All rights reserved.