Electron Production by Associative Detachment of O– Ions with NO, CO, and H2

Abstract

Electron currents resulting from associative-detachment processes involving O– ions have been observed in a drift tube containing mixtures of oxygen and either hydrogen, carbon monoxide, or nitric oxide. The associative-detachment rate coefficients are obtained from analyses of the electron current waveforms. The results indicate that the associative detachment proceeds by a two-body process. The observed rate coefficients are consistent with results obtained from studies of O– destruction using mass spectrometric techniques. Associative detachment rate coefficients of 2.2, 6.5, and 7.5 × 10− 10 cm3 sec− 1 have been measured at near-thermal ion energies for the O– + NO, O– + CO, and the O– + H2 reactions, respectively. The average energy of the O– ions ranged from thermal up to 0.16 eV. A search for a reaction between O2– and CO was unsuccessful indicating that the rate coefficient of this reaction is less than 10− 14 cm3 sec− 1.