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

1973 ◽  
Vol 51 (3) ◽  
pp. 370-372 ◽  
Author(s):  
R. Atkinson ◽  
R. J. Cvetanović
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Atom ◽  
Phase Shift ◽  
Rate Constants ◽  
Hydrogen Atoms ◽  
Arrhenius Parameters ◽  
Modulation Technique ◽  
The Absolute

A modulation technique has been used to determine from phase shift measurements the absolute values of the rate constants and the Arrhenius parameters of the reaction of hydrogen atoms with nitric oxide.

Determination of rates of hydrogen atom reactions with alkenes at 298 K by a double modulation technique

1979 ◽  
Vol 57 (7) ◽  
pp. 777-784 ◽  
Author(s):  
K. Oka ◽  
R. J. Cvetanović
Keyword(s):  
Rate Constants ◽  
Slow Component ◽  
Gaseous Mixture ◽  
Hydrogen Atoms ◽  
Chemiluminescence Intensity ◽  
Gaseous Mixtures ◽  
Rate Of Decay ◽  
The Absolute ◽  
Double Modulation

Hydrogen atoms and HgH radicals are the two precursors of the HNO(1A′′) chemiluminescence in the mercury photosensitized reaction of gaseous mixtures of H2, NO, and Hg and are responsible, respectively, for its slow and fast decaying component. The total intensity of the chemiluminescence is decreased when an olefin is added to the gaseous mixture and, with an excess of the olefin added, 85% of the luminescence is eliminated. This fraction corresponds to the slow component of the chemiluminescence, due to the reaction H + NO + M → HNO* + M, while the residual 15% is due to the reaction HgH + NO → HNO* + Hg. The magnitudes of the decrease of chemiluminescence intensity and of the increase of the rate of decay of its slow component at a given concentration of an added olefin provide information on the rate of H atom reaction with the olefin.Relative values of the rate constants of H atom reactions with ethylene, propene, 1-butene, cis-2-butene, trans-2-butene, isobutene, and 1,3-butadiene have been determined in the present work from the observed dependence of the luminescence intensity on olefin concentration. At the same time, the absolute values of these rate constants have been determined from the relation between the decay rate of the slower component of the chemiluminescence and olefin concentration. The relative and the absolute values of the rate constants are compared with each other, to check their mutual consistency, and with the available relative and absolute values in the literature.

Temperature dependence of rate constants for the reactions of oxygen atoms, O(3P), with HBr and HI

1978 ◽  
Vol 56 (23) ◽  
pp. 2934-2939 ◽  
Author(s):  
D. L. Singleton ◽  
R. J. Cvetanović
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Standard Deviation ◽  
Phase Shift ◽  
Rate Constants ◽  
Bond Energy ◽  
Bond Order ◽  
Shift Technique ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

Rate constants for the reactions O(3P) + HX → OH + X (X = Br, I) have been determined by a phase shift technique. Oxygen atoms were generated by modulated mercury photosensitized decomposition of nitrous oxide, and were monitored by the chemiluminescence from the reaction with nitric oxide. Over the temperature interval 298–554 K, the rate constants are satisfactorily represented by the Arrhenius expressions kO+HBr = (8.09 ± 0.86) × 109 exp (−3.59 ± 0.08)/RT and kO+HI = (2.82 ± 0.27) × 1010 exp (−1.99 ± 0.07)/RT, where the units are ℓ mol−1 s−1 and kcal mol−1. The indicated uncertainties are one standard deviation. The results of bond energy–bond order calculations, incorporating recently proposed modifications, are discussed.

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