Determination of the Rates of Hydrogen Atom Reaction with NO by a Modulation Technique

The mechanism of the photolysis of formaldehyde was studied in experiments a t 3130 A and in the pressure range of 1-12 torr at 25°C. The experiments were designed to establish the quantum yields of the primary decomposition steps (1) and (2), CHzO + hv -H + HCO (I): CH20 + hv -Hz + CO (2), through the effects of added isobutene, trimethylsilane, and nitric oxide on Qco and Q H~ The ratio Qco/+H, was found to be 1.01 f 0.09(2a) and (+H, + Qpc0)/2 = 1.10 f 0.08 over the range of pressures and a 12-fold change in incident light intensity. Isobutene and nitric oxide additions reduced +H, to about the same limiting value, 0.32 f 0.03 and 0.34 f 0.04, respectively, but these added gases differed in their effects on Qco. With isobutene addition Qco/QH~ reached a limiting value of 2.3; with NO addition Qco exceeded unity. The addition of small amounts of MeBSiH reduced +)H, to 1.02 f 0.08 and lowered Qco to 0.7. These findings were rationalized in terms of a mechanism in which the "nonscavengeable," molecular hydrogen is formed in reaction (2) with $2 = 0.32 f 0.03, while the "free radical" hydrogen is formed in reaction (1) with = 0.68 f 0.03. In the pure formaldehyde system these reactions are followed by (3)- (5)

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Determination of the Rates of Hydrogen Atom Reaction with NO by a Modulation Technique

Cited by 16 publications

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An experimental, theoretical and kinetic-modeling study of the gas-phase oxidation of ammonia

An experimental, theoretical and kinetic-modeling study of the gas-phase oxidation of ammonia

Atmospheric Chemical Kinetics Data Survey

The quantum efficiency of the primary processes in formaldehyde photolysis at 3130 Å and 25°C

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