Reactions of the O– negative ion with hydrogen and the lower hydrocarbons

Abstract

The reactions between O^–, formed by dissociative attachment to oxygen, and H₂, D₂, CH₄, C₂H₆, C₂H₄ and C₂H₂ have been studied using a drift tube and mass filter. Gas densities ranged over a factor of five about 10¹⁷ molecule cm^–3 and reduced fields were of the order of 3 × 10^–16 V cm² molecule^–1. The reaction with the alkanes gave a single pair of products R + OH^–, but the remainder produced both negative ions and free electrons. The following rate constants were measured and with the minor exception of OH^– production from C₂H₄ were found to be substantially independent of the reduced field. [graphic omitted] The reaction with C₂H₄ also produced OH^–, C₂H^–, C₂OH^– and C₂H₃O^– at rates of 0.5 to 10, 5, 1.5 and 2 % respectively of the combined rate of the two major channels.

The upper limits for the rates of the reactions of O^–₃ with the same molecules were two orders of magnitude lower.