ELECTRON DETACHMENT AND CHARGE-TRANSFER FOR COLLISIONS OF O- AND S- WITH H

Total electron-detachment and charge-transfer cross sections for collisions of O- and S- with atomic hydrogen have been measured for relative collision energies E ranging from 0.1 to 15 eV. At low collision energies these results are fairly well described by a simple Langevin orbiting model and, in the case of O- (where intermolecular potentials are available), a simple curve-crossing model is also in reasonable accord with the measurements. Neither O- + H nor S- + H displays an energetic barrier to associative detachment. Charge-transfer cross sections are small for both systems for the range of collision energies sampled in the experiment. Associative detachment cross sections are also reported for S- + H-2 for E < 2 eV; the results appear to resolve an apparent discrepancy between previous measurements.