Homogeneous rate of recombination of hydrogen atoms

1968 ◽  
Vol 46 (6) ◽  
pp. 1005-1015 ◽  
Author(s):  
F. S. Larkin
Keyword(s):  
Rate Constants ◽  
Hydrogen Atoms ◽  
First Order ◽  
A Value ◽  
Rate Of Decay ◽  
Low Levels ◽  
Three Body ◽  
Conventional Type ◽  
Order Surface ◽  
Body Recombination

The rate of decay of hydrogen atoms has been measured in a conventional type of discharge-flow system at temperatures between 190–350 °K. The recombination fitted the equation[Formula: see text]where ks is the first order surface rate constant. No three-body recombination for M = H was observed at the low levels of dissociation (2–5%) employed. When the flow gases contained traces of water vapor and (or) oxygen as impurities, the homogeneous rate constants (k2,M) had a small positive activation energy which was due to the influence of a surface reaction between hydrogen atoms and the impurities. In the absence of impurities, true homogeneous rate constants were obtained. A value of k2,Ar = 4.6 ± 0.5 × 1015 cm6 mole−20s−1 was found at 291 °K. The temperature variation was approximately T−1/2 over the range 190–350 °K.

Estimation of Three‐Body Recombination Rate Constants

1964 ◽  
Vol 40 (4) ◽  
pp. 1166-1167 ◽  
Author(s):  
Benjamin J. Woznick ◽  
James C. Keck
Keyword(s):  
Rate Constants ◽  
Recombination Rate ◽  
Three Body ◽  
Body Recombination

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.

The association of oxygen atoms and their combination with nitrogen atoms

1967 ◽  
Vol 296 (1445) ◽  
pp. 222-232 ◽  
Keyword(s):  
Activation Energy ◽  
Temperature Coefficient ◽  
Rate Constants ◽  
Room Temperature ◽  
Kinetic Studies ◽  
Active Nitrogen ◽  
Similar Temperature ◽  
Three Body ◽  
Body Recombination ◽  
Oxygen Atoms

The rate constants of the reactions N + O + M = NO + M (2) O + O + M = O 2 + M (4) have been determined in active nitrogen systems, nitric oxide being added to result in the partial production of oxygen atoms. The concentrations of these atoms were monitored by measurements of the intensity of the N 2 First Positive emission and NO β emission. The following rate constants (in cm 6 mole –2 s –1 ) were obtained at room temperature (298 °K) N 2 Ar He 10 –15 k 2 3.88 ± 0.30 2.98 ± 0.35 1.36 ± 0.17 10 -14 k 4 11.3 ± 1.1 6.0 ± 0.6 4.6 + 0.4 In the range 196 to 327 °K, the temperature coefficient of reaction (2) corresponds to a T -½ dependence or an activation energy of –270 ± 120 cal/mole. This is unusually small for a three body recombination and contrasts with more ‘normal’ activation energy of –1420 ±350 cal/mole found for reaction (4). The NO β emission associated with reaction (2) has a similar temperature coefficient to the overall reaction, but is slightly enhanced by replacing the nitrogen carrier by argon. Our kinetic studies of this emission generally confirm the mechanism of Young & Sharpless (1962).

THREE-BODY RECOMBINATION OF GASEOUS IONS

1960 ◽  
Vol 38 (10) ◽  
pp. 1693-1701 ◽  
Author(s):  
Takayuki Fueno ◽  
Henry Eyring ◽  
Taikyue Ree
Keyword(s):  
Binding Energy ◽  
Theoretical Approach ◽  
Rate Constants ◽  
Lennard Jones Potential ◽  
Internuclear Separation ◽  
Jones Potential ◽  
Lennard Jones ◽  
Three Body ◽  
Body Recombination ◽  
Complex Ion

The recombination of gaseous ions in the presence of third bodies is assumed to follow a sequence of two bimolecular steps: M + X+ [Formula: see text] MX+ and MX+ + Y− [Formula: see text] XY + M. The termolecular rate constants of the over-all processes are calculated for several ionized gases at various temperatures. For the calculation, the equilibrium internuclear separation and the corresponding binding energy of a complex ion, MX+, are obtained by minimizing the interaction energy between M and X+, which is approximated to the sum of the Lennard-Jones potential for the M–X interaction and the polarization energy between M and X+. The recombination coefficients of some ionized gases at 288 °K and various pressures are calculated and compared with the observed data. The agreement is found to be satisfactory. The limitations of this theoretical approach are discussed.

THE LIFETIME OF THE STATE OF N2

1965 ◽  
Vol 43 (2) ◽  
pp. 369-374 ◽  
Author(s):  
L. F. Phillips
Keyword(s):  
Decay Rate ◽  
Rate Constant ◽  
Rate Constants ◽  
Blue Emission ◽  
Order Rate Constant ◽  
The State ◽  
Active Nitrogen ◽  
First Order ◽  
A Value ◽  
Mean Lifetime

The decay of the blue emission from the active nitrogen – iodine flame has been measured at iodine pressures down to 1.4 × 10−4 torr. Extrapolation of the decay rate to zero iodine pressure yields a value of 0.89 ± 0.41 s−1 for the first-order rate constant in absence of iodine, corresponding to a mean lifetime of 1.1 s for the [Formula: see text] state of N2. The rate constants for the reactions[Formula: see text]and[Formula: see text]are (2.6 ± 0.3) × 10−11 exp (−68 ± 34/RT) and (8.3 ± 1.2) × 10−14 cm3 molecule−1 s−1 respectively.

Performance and Modelling of a Highway Wet Detention Pond Designed for Cold Climate

2009 ◽  
Vol 44 (3) ◽  
pp. 253-262 ◽  
Author(s):  
Jes Vollertsen ◽  
Svein Ole Åstebøl ◽  
Jan Emil Coward ◽  
Tor Fageraas ◽  
Asbjørn Haaning Nielsen ◽  
...  
Keyword(s):  
Rate Constants ◽  
Pond Water ◽  
Pollutant Removal ◽  
Cold Climate ◽  
Traffic Load ◽  
Substantial Part ◽  
First Order ◽  
Detention Pond ◽  
Time Of Year ◽  
Wet Detention Pond

Abstract A wet detention pond in Norway has been monitored for 12 months. The pond receives runoff from a highway with a traffic load of 42,000 average daily traffic. Hydraulic conditions in terms of inflow, outflow, and pond water level were recorded every minute. Water quality was monitored by volume proportional inlet and outlet samples. During most of the year, excellent pollutant removal was achieved; however, during two snowmelt events the pollutant removal was poor or even negative. The two snowmelt events accounted for one third of the annual water load and for a substantial part of the annual pollutant discharge. The performance of the pond was analyzed using a dynamic model and pollutant removal was simulated by first-order kinetics. Good agreement between measurement and simulation could be achieved only when choosing different first-order rate constants for different parts of the year. However, no relation between the rate constants obtained and the time of year could be identified, and neither did the rate constants for different pollutants correlate. The study indicates that even detailed measurements of pollutant input and output allow only average performance to be simulated and are insufficient for simulating event-based variability in pond performance.

Submerged upflow biotower operation and computer simulation

1994 ◽  
Vol 30 (11) ◽  
pp. 143-146
Author(s):  
Ronald D. Neufeld ◽  
Christopher A. Badali ◽  
Dennis Powers ◽  
Christopher Carson
Keyword(s):  
Computer Simulation ◽  
Benzoic Acid ◽  
Computer Model ◽  
Rate Constants ◽  
Batch Mode ◽  
Operational Conditions ◽  
First Order ◽  
Low Concentrations ◽  
Biological Transformation ◽  
Kinetics Of

A two step operation is proposed for the biodegradation of low concentrations (< 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.

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