Final States in the Dissociative Excitation of Molecular Hydrogen

The dissociative excitation H₂+e→H(2s)+H+e has been studied with a time-of-flight method. Measurements of the excitation function and the angular distribution of the metastable atoms show that the slow atoms arise from dissociation out of e³Σᵤ⁺ and B^'¹Σᵤ⁺ states and from predissociation out of the d³Πᵤ⁺ and D¹Πᵤ⁺ states. The fast atoms arise from a previously unreported ¹Πᵤ state that corresponds to a separated-atom limit in which both atoms are in $n=2$ states.