In search of new resonance structures in dissociative photoionization of H 2

We present a theoretical study of dissociative photoionization of H 2 via the 1 Π u symmetry in the photon energy range 30–43 eV. Our results explain the various peaks observed in the experiments below 40 eV and illustrate, in particular, the important role of the 2 Π u (2 p π u ) ionization threshold. At higher photon energies, they suggest the existence of new resonance structures that may be associated with doubly excited states of H 2 lying above the third and fourth ionization thresholds (the Q 3 and Q 4 resonance series). From the calculated resonance parameters, we conclude that the dominant mechanism at high photon energies should involve the Q 4 (and probably higher) doubly excited states of H 2 . © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2002