摘要:

AbstractThe generation of metastable O2(1Σg+) and O2(1Δg) in the H + O2system of reactions was studied by the flow discharge chemiluminescence detection method. In addition to the O2(1Σg+) and O2(1Δg) emissions, strong OH(v= 2) → OH(v= 0), OH(v= 3) → OH(v= 1), HO2(2A′000) → HO2(2A″000), HO2(2A′001) → HO2(2A″000), and H O2(2A″200) → HO2(2A″000) emissions were detected in the H + O2system. The rate constants for the quenching of O2(1Σg+) by H and H2were determined to be (5.1 ± 1.4) × 10−13and (7.1 ± 0.1) × 10−13cm3s−1, respectively. An upper limit for the branching ratio to produce O2(1Σg+) by the H + HO2reaction was calculated to be 2.1%. The contributions from other reactions produ

ISSN:0538-8066    

DOI:10.1002/kin.550201202

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractA flow system has been developed to study relative rate coefficients of hydroxyl radicals reacting with alkanes under conditions relating to tropospheric chemistry. Relative Arrhenius parameters have been measured over the temperature range 243–328 K for pairs of alkanes from a list consisting ofn‐butane, 2‐methylpropane,n‐pentane,n‐hexane, 2,2‐ and 2,3‐dimethylbutane, 2,3,3‐trimethylbutane, and 2,3,4‐trimethylpentane.The results have been incorporated into a Structure‐Activity Relation for hydroxylalkane reactions which leads to the following group rate coefficients for a temperature range of 240–500 K.\documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{rcl} k_{{\rm prime}}^0 &=& 3.13 \times 10^{ - 12}\, {\rm exp(} - 904/T)\,{\rm cm}^{\rm 3}\, {\rm molecule}^{ - 1}\, {\rm s}^{ - 1} \\ k_{{\rm sec}}^0 &=& 2.45 \times 10^{ - 12} \,{\rm exp(} - 320/T)\,{\rm cm}^{\rm 3}\, {\rm molecule}^{ - 1}\, {\rm s}^{ - 1} \\ k_{{\rm tert}}^0 &=& 1.88 \times 10^{ - 12} \,{\rm cm}^{\rm 3}\, {\rm molecule}^{ - 1}\, {\rm s}^{ - 1} \end{

ISSN:0538-8066    

DOI:10.1002/kin.550201203

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractDirect kinetic measurements have been made on the reaction: 2NO2= N2O4. Equilibrium mixtures of NO2and N2O4at (224 ± 2) K were perturbed by flash photolysis of a fraction of the N2O4. The rate of relaxation back to equilibrium was monitored by observing the transmittance of the 14P(11) line from a cw CO laser selected to coincide with thev9band of N2O4. Measurements were made in the presence of 350–750 torr of He, N2, or CF4. Within this limited pressure range, the kinetics were consistent with third‐order behavior with the following rate constants (cm3molecule−1s−1):k0= (2.4 ± 0.5) × 10−34[He]; (1.0 ± 0.1) × 10−33[N2]; (1.8 ±

ISSN:0538-8066    

DOI:10.1002/kin.550201204

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractHeterogeneous recombination of O + CO → CO2over a solid CO2surface at 77 K was investigated. A modified discharge flow setup was used to generate low O atom concentrations by the reaction N + NO → N2+ O(3P). The O atom concentrations were measured upstream and downstream of the solid CO2substrate using resonance fluorescence by monitoring the unresolved 130.3 nm triplet transition3S1−3P2,1,0at the two fixed points. CO2formed was determined by measuring the β activity from C14O2produced from CO containing C14O as a reactant gas. The CO2formation was found to be first order in CO and independent of O atom concentration over the entire range of 4.3 × 1012to 1.9 × 1014cm−3and 1.2 × 1011to 5.6 × 1012cm−3for CO and O respectively. The first order recombination coefficient, λCOwas found to be 1.

ISSN:0538-8066    

DOI:10.1002/kin.550201205

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractA recently developed solution of the master equation for unimolecular and recombination reactions is extended to give new means for incorporating angular momentum (J) conservation in the fall‐off regime for multichannel reactions. The calculated pressure dependence of a typical multichannel unimolecular dissociation reaction (thermal dissociation of 1‐iodopropane) shows that if one of the channels has a transition state with a moment of inertia (I†) significantly different from that of the parent molecule (I) (e.g., a “simple‐fission” type), neglect of angular momentum conservation causes the predicted branching ratio to be grossly in error at lower pressures. Specifically, if I†>I the rate coefficient is underestimated whereas if I†

ISSN:0538-8066    

DOI:10.1002/kin.550201201

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY