Interference, confinement and non Franck-Condon effects in photoionization of H2 molecules at high photon energy

We study in detail photoionization of H2 molecules by high energy photons. Bound and continuum states are accurately evaluated by using B-spline basis functions. The usual Franck-Condon behavior is not followed when the molecule is parallel to the polarization direction. The origin of this anomaly is related to interference effects. Moreover, it is shown that at these high photon energies, the nuclear asymmetry parameter exhibits a reminiscence of these interference patterns.