Dynamics of the Reaction of N+ with H2

The reaction N⁺(H₂, H)NH⁺ has been investigated by measuring the velocity vector distribution of product ions formed when a collimated, mass‐analyzed beam of reactant ions impinges on a target gas. In the 2.5–8.1‐eV range of initial relative energies, the reaction proceeds by a direct interaction mechanism with predominant forward scattering. The forward‐scattered NH⁺ is more excited internally than would be expected from the spectator stripping model, and the internal excitation markedly decreases as the scattering angle increases. There is evidence that at initial relative energies below 4 eV, the principal product is NH⁺ in the $a^4{\Sigma }^{-}$ state, while at initial relative energies above 6.5 eV, the $X^2\Pi$ state of NH⁺ is formed predominantly.