Attosecond photoionization of a coherent superposition of bound and dissociative molecular states: effect of nuclear motion

We study numerically the possibility for monitoring electron motion in a dissociating molecule using an attosecond XUV probe pulse which photoionizes a coherent superposition of two nuclear wave packets. We present the photoelectron spectra and forward–backward asymmetries in these spectra obtained from a numerical solution of the time-dependent Schrödinger equation for one electron and two protons both moving in 1D, along the laser polarization vector. In our (non-Born–Oppenheimer) approach the 1D dissociative ionization of the model H2 with softcore potential is described exactly. We find that in general the nuclear motion in a fast moving light molecule does not wash out the oscillations as function of the time delay between XUV probe and the pump pulses as expected from the model with fixed nuclei. (Some figures in this article are in colour only in the electronic version)