Dissociative excitation of H2 by electron impact: Translational spectroscopy of long lived high Rydberg fragment atoms

Abstract

Electron impact excitation of H2 leads to three distinguishable groups of high Rydberg fragment atoms. High Rydberg molecules are also detected. The measurements consist of (1) excitation functions and (2) time of flight distributions which are transformed to fragment translational energy distributions. For high Rydberg fragments from molecular high Rydberg states converging to the repulsive wall of the H+2 ground state, the measured and calculated kinetic energy distributions agree, in accordance with the prediction of the core ion model of high Rydberg dissociation. The remaining high Rydberg fragments result from dissociation of states of H2 with both electrons excited to low principal quantum numbers rather than from dissociation of molecular high Rydberg states.