Electron Attachment and Detachment. II. Mixtures of O2 and CO2 and of O2 and H2O

Electron-attachment coefficients in O2–CO2 and O2–H2O mixtures and electron-attachment—detachment equilibrium constants for O2–CO2 mixtures are obtained from drift-tube measurements similar to those used previously for O2. The three-body attachment coefficients involving O2 and CO2 are 3.1×10−30, 4.0×10−30, and 2.7×10−30 cm6/sec at 300°, 477°, and 525°K. The electron—negative-ion equilibrium constant data correspond to the formation of a CO4− with a large degree of freedom of internal motion and with an energy of dissociation into O2− and CO2 of 0.8 eV. The three-body attachment coefficient involving O2 and H2O is 1.4±0.2×10−29 cm6/sec at 300° and 395°K. In O2–H2O mixtures at temperatures of 500° and 555°K we observe the conversion of O2− to a more stable negative-ion form which shows no evidence of dissociation or detachment.