Mechanism of thermal electron attachment in N/sub 2/O--CO/sub 2/ mixtures in the gas phase
The attachment of thermal electrons to nitrous oxide in N/sub 2/O--CO/sub 2/ mixtures has been studied at room temperature in the pressure range 5--120 torr. Ionization was by pulse radiolysis and the electron concentration was measured as a function of time by microwave conductivity. Addition of even less than 0.1% CO/sub 2/ to N/sub 2/O causes a marked increase in attachment rate. However, this enhancement soon saturates in that further additions of CO/sub 2/ have less and less effect. Experiments with ternary mixtures including C/sub 2/H/sub 6/ showed a further enhancement which was much larger than the additive effects of CO/sub 2/ and C/sub 2/H/sub 6/ alone. These observations can be explained by a two step three-body process producing vibrationally excited N/sub 2/O/sup -/* if the rate constant for stabilization of N/sub 2/O/sup -/* by CO/sub 2/ is 4 x 10/sup -30/ cm/sup 6//molecule/sup 2/xsec. The decrease in effectiveness with increased CO/sub 2/ pressure is interpreted as the collisional ionization of a complex ion, (N/sub 2/OxCO/sub 2/)/sup -/*. The nonadditive effect of hydrocarbon results from the rapid reactive destruction of such complexes by collision with the hydrocarbon. A detailed quantitative treatment of the proposed mechanism was successful in explaining most features of the data. In a limited set of experiments, allene : N/sub 2/O mixtures were found to behave much like CO/sub 2/--N/sub 2/O.
- Research Organization:
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556
- OSTI ID:
- 6535068
- Journal Information:
- J. Chem. Phys.; (United States), Vol. 69:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON DIOXIDE
ELECTRON-MOLECULE COLLISIONS
ELECTRON ATTACHMENT
NITROUS OXIDE
IONIZATION
MIXTURES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
COLLISIONS
DISPERSIONS
ELECTRON COLLISIONS
MOLECULE COLLISIONS
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena