Collision processes of electrons with molecular hydrogen ions

Collision processes of electrons with trapped ions of mass numbers 1, 2, 3, 5, 7, 10, 14 and 20 are investigated in the concentric electron-beam device. Trapping characteristics are measured and lead to the conclusion that all the ions in the trap are hydrogenic. Cross section functions for the electron impact dissociation of H 2 + , H 3 + and H 5 + are measured. The shape of the H 2 + dissociation indicates that the molecular ions are trapped for a sufficiently long time for vibrational decay to upsilon =0 to occur. There is good agreement between the present low energy H 3 + dissociation data and previous work. Dissociation cross sections for H 5 + and the temperature dependence of the e-H 5 + recombination rate are measured. The latter is in good agreement with previous room temperature data and facilitates the prediction of the recombination rate in the Jovian atmosphere.