The collision-induced dissociation of ${\mathrm{H}}_3^{+}$ on He at a relative energy of 4.8 keV was performed. The laboratory energy distributions of ${\mathrm{H}}^{\mathrm{-}}$ and ${\mathrm{H}}^{+}$ were measured. The energy-analyzed spectrum of ${\mathrm{H}}^{\mathrm{-}}$ was measured in coincidence with ${\mathrm{H}}^{+}$, and the energy-analyzed spectrum of ${\mathrm{H}}^{+}$ was measured in coincidence with ${\mathrm{H}}^{\mathrm{-}}$. From these results, the energy absorbed by the ${\mathrm{H}}_3^{+}$ molecule in the excitation process induced by the collision with He previous to its breakup, was evaluated. The center-of-mass energy distributions of both fragments (${\mathrm{H}}^{\mathrm{-}}$ and ${\mathrm{H}}^{+}$) were obtained, and from these the average angle between the positive fragments was determined, as well as the mean total kinetic energy gained by the fragments, and the most probable energy for both charged products. Comparisons with previous measurements are given.

• Received 25 March 1994

DOI:https://doi.org/10.1103/PhysRevA.50.3856