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.

A novel ozone source was developed to study the negative ion chemistry of ozone in the gas phase. Rate constants and product ion branching fractions are reported for 17 negative ion−molecule reactions involving ozone (O3). This is the most comprehensive set of O3 reactions with negative ions to date. The reactions proceed primarily through charge transfer and O atom transfer. The reaction rate constants for O-, O2 -, and OH- are large and approximately equal to the thermal energy capture rate constant given by the Su-Chesnavich equation based on average dipole orientation theory. The negative ions NO2 -, CO4 -, SF6 -, and PO2 - are somewhat less reactive, reacting at approximately 20−50% of the thermal capture rate. The hydrofluorocarbon ions CF3 - and C2F5 - react at 80% of the thermal capture rate, and F- is the major product ion formed. NO3 -, CO3 -, PO3 -, CF3O-, F-, Cl-, and Br- are found to be unreactive with rate constants < 5 × 10-12 cm3 s-1, which is the present detection limit of our apparatus using this ozone source. The I- ion was observed to cluster with O3 to form IO3 - with a rate constant of approximately 1 × 10-11 cm3 s-1, which is a factor of 2 above our detection limit, and no other product channels were observed. All of the anions listed above showed no reactivity, k < 5 × 10-13 cm3 s-1, with O2.