Reactions of O with Some Triatomic Molecules

Energy analysis of the OH product ion indicated that, at reactant ion energies above 6 eV, the reaction proceeds through H atom pickup, rather than through an H202 complex. 

The reaction of O ions with CO2 leads to the formation of both 02 + CO and C02 + O, by the reactions 

Reaction (23) is spin-allowed and endothermic by 1.37 eV (assuming the electron affinity of O2 is 0.43 eV ) for ground-state reactants and products. The cross section shows a threshold at approximately the expected ion energy, i.e., 2 eV (lab), and reaches a maximum of 0.2 x 10 cm at 12 eV. Reaction (24), which is one of the three presently known processes by which CO2 may be formed in the gas phase, is discussed later in this chapter. Associative detachment is not expected to be an important reaction in 

Additional Reactions with Diatomic and Triatomic Molecules 

Several negative-ion-neutral reactions have been studied, principally in an attempt to determine limits for the electron affinities of important diatomic and triatomic molecules. In the more widely used method, one looks for charge transfer between a low-energy (preferably thermal), negative ion X and the neutral molecule Y. Alternatively, the kinetic energy threshold for an endothermic charge transfer reaction between X and Y is measured. 

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