Ionization and excitation of hydrogen molecules by fast proton impact

The ratio of ionization - excitation to single ionization of hydrogen molecules caused by fast proton impact was measured over a wide velocity range (v = 6 - 24 au) using the coincidence time-of-flight technique. This ratio, %, is independent of the collision velocity at high velocities. It differs from the ratio of total to production mostly due to a large contribution from the dissociation of the electronic ground state of the molecular ion. The dissociation fraction of was measured and compares well with our calculations using the Franck - Condon approximation.