ELECTRON PRODUCTION BY ASSOCIATIVE DETACHMENT OF O-IONS WITH NO CO AND H2

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.