ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
The reaction of electronically excited O(1D) atoms with CO2 to form CO+O2(1Σ+g,1Δg,3Σ−g) has been probed with second-derivative modulated diode laser spectroscopy. The O(1D) atoms were generated by the pulsed 193 nm laser photolysis of N2O, and the reaction was followed by monitoring the formation of CO as a function of the number of laser pulses. These experiments have revealed that the quantum yield for this reaction is (2.1±0.3)×10−3 molecules/photon absorbed. The very low quantum efficiency suggests that a significant potential barrier exists on the reaction coordinate which prevents the vast majority of collisions from fragmenting into products distinguishable from reactants. The rate constant, measured indirectly by comparison with the rate constant for quenching, is found to be (2.4±0.5)×10−13 cm3 molecule−1 s−1 and represents the best estimate currently available in the literature for the reaction rate constant. In experiments involving 16O(1D)+12C18O2, the resulting product, 12C18O, indicates that no isotopic exchange takes place in the reaction. Comparison with deactivation results suggests that the reaction proceeds by a simple, direct oxygen-atom abstraction with a potential barrier, whereas the quenching channel involves a long-lived intermediate.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.457278
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