Production of H+ fragments from H2 by fast projectiles

The yield of H⁺ fragments from H₂ by fast beams (0.5-4 MeV) of H⁺, H⁺₂, He⁺, and O⁺ is measured as a function of projectile velocity. The yields of H⁺ from both the dissociative states of H⁺₂ and from the double ionization of H₂ are identified. The H⁺₂ projectile is comparable to He⁺ in producing H⁺ fragments from the single ionization of the H₂ target, but unlike He⁺ it produces no appreciable double ionization.