TEMPERATURE DEPENDENCE OF ONSET FOR NEGATIVE-ION FORMATION CO2

We have studied the formation of O- ions with zero kinetic energy from CO2, a reaction typical of the forms e-+XYZ→X-+YZ or →XY-+Z, where XYZ is a triatomic molecule. We find that the onset energy shows a marked dependence on the temperature of the gas, and we conclude that such onset measurements must be extrapolated to 0°K to give meaningful electron affinities. © 1969 The American Physical Society.