Ionisation and electron capture in collisions of slow H+and He2+ions with hydrogen

Publisher Website
Google Scholar
Abstract
A crossed-beam technique previously used in the authors' laboratory for studies of ionisation of H2 by H+ and He2+ impact in the ranges 38-1500 and 31-550 keV amu-1, respectively, has been adapted to permit measurements to be extended down to 10 keV amu-1. Both ionisation and electron capture have been studied using time-of-flight mass spectroscopy together with electron-slow-ion and slow-ion-fast-ion coincidence counting of the collision products. Separate cross sections for non-dissociative and dissociative electron capture and ionisation channels have been determined. Some significant discrepancies between the authors' results and previous measurements due to Afrosimov et al. (1969) are noted. At their lowest impact energies electron capture substantially exceeds ionisation. In addition, for He2+ impact, unlike protons, dissociative ionisation and transfer ionisation cross sections substantially exceed those for non-dissociative ionisation.