Merging beams study of the H2+(H2,H)H3+, H2+(D2,H)HD2+, and D2+(H2,H)HD2+ reaction mechanisms

A merging beams apparatus was used to measure energy distributions of ions formed in the ${\mathrm{H}}_2^{+}({\mathrm{H}}_2,\mathrm{H}){\mathrm{H}}_3^{+}$ reaction for collisions with relative energy W in the range 0.1 eV≤W≤10.0 eV. The major components of the reaction, proton and hydrogen atom transfer, were resolved through study of the ${\mathrm{H}}_2^{+}({\mathrm{D}}_2,\mathrm{H}){\mathrm{HD}}_2^{+}$ and ${\mathrm{D}}_2^{+}({\mathrm{H}}_2,\mathrm{H}){\mathrm{HD}}_2^{+}$ reactions, respectively. Each component follows predominantly direct interactions at all energies studied and contributes nearly equally to the ${\mathrm{H}}_2^{+}({\mathrm{H}}_2,\mathrm{H}){\mathrm{H}}_3^{+}$ reaction for W≤6 eV. At higher energies, hydrogen atom transfer becomes increasingly more important; the final relative energy W′ agrees qualitatively with the abandoned atom model. The growth of a satellite peak for W > 7 eV indicates the appearance of an electronically excited product.