Dissociative photoionization of H2 from 18 to 124 eV

Absolute cross sections for the production of H+ and H2+ have been measured from the dissociative ionization threshold at 18.076–124 eV. A broad resonance occurs in the H+ cross section caused primarily by autoionization of the Q1 Rydberg states. The absolute cross section for producing neutral atoms only is obtained by the use of published photoionization yield data. It is shown that the sum of the neutral and ionized H fragments produce a major resonance representing transitions into the Q1 and Q2 Rydberg states.