Thermal reactions of O − ions with saturated hydrocarbon molecules

The thermal energy reactions of O − ions with saturated, hydrocarbon molecules have been investigated in a flowing afterglow of pure oxygen and a mixture of helium and oxygen. Hydrogen atom abstraction was found to be the dominant reaction channel. The reaction probability was found to increase for the higher members of the homologous series. The further reaction of the product OH − ions with saturated hydrocarbon molecules was not observed. This result was used to estimate an upper limit to the electron affinity of the free radicals CH 3 , C 2 H 5 , C 3 H 7 , and C 4 H 9 .