Kinetics for the reactions of O- and O2- with O2(a1Deltag) measured in a selected ion flow tube at 300 K.

The kinetics of the reactions of O- and O2- with O2(a1Deltag) have been studied at 300 K in a selected ion flow tube (SIFT). The O2(a1Deltag) concentrations have been determined using emission at 1270 nm from the O2(a1Deltag, v=0-->X3Sigmag-, v=0) transition measured with an InGaAs detector calibrated against absolute spectrally dispersed emission measurements. The rate constants measured for O- and O2- are 1.1x10(-10) and 6.6x10(-10) cm3 s-1, respectively, with uncertainties of +/-35%. The O2- reaction only produces electrons and can be described as Penning detachment, while the O- reaction has been found to produce both O2- and e-. The O2- branching fraction has a lower limit of approximately 0.30. Comparison of the present results to previous measurements found in the literature provides a resolution to a previous discrepancy in the rate constant values.