Autoionizing decay of H2 doubly excited states by using xuv-pump-infrared-probe schemes with trains of attosecond pulses

We present a theoretical study of H-2 ionization by a pump-probe scheme consisting on an attosecond pulse train (APT) and a near-infrared (IR) pulse. We focus on the autoionization dynamics of the first series of resonant states of the molecule, the Q(1) doubly excited states. The APT central frequency is tuned to populate the (1)Sigma(+)(u) resonant states. The trace of autoionization is clearly visible in the two-dimensional (2D) proton-electron coincidence spectra and in the proton kinetic energy spectra. The dynamics of the autoionization process is clearly visible in the movie obtained by plotting the 2D spectrum as a function of the time delay between the APT and IR pulses. An analysis of the final symmetries Sigma(g) and Sigma(u) allows us to track the origin of the different structures.