A Method for Evaluating Rate Constants in the Jablonski Model of Excited Species in Rigid Glasses

1959 ◽  
Vol 63 (1) ◽  
pp. 15-16 ◽  
Author(s):  
E. H. Gilmore ◽  
E. C. Lim
Keyword(s):  
Rate Constants ◽  
Excited Species

Deactivation of O(1S) and O2(b1Σg+)

1969 ◽  
Vol 47 (10) ◽  
pp. 1870-1877 ◽  
Author(s):  
F. Stuhl ◽  
K. H. Welge
Keyword(s):  
Rate Constants ◽  
Excited Species ◽  
Intensity Decay

Rate constants for the collisional deactivation of O(1S) and O2(b1Σg+) are reported. They are obtained by measuring the intensity decay of the O(1S → 1D) and O2(b1Σg+ → X2Σg+) emissions after a pulsed production of the excited species.

Collisional Deactivation Rates of Electronically Excited Molecular Ions. II

1972 ◽  
Vol 50 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. I. Mackay ◽  
R. E. March
Keyword(s):  
Rate Constants ◽  
Radiative Lifetime ◽  
Molecular Ions ◽  
Deactivation Rate ◽  
Complete Knowledge ◽  
Induced Dipole ◽  
Excited Species ◽  
Vibrational Levels ◽  
Electronically Excited ◽  
Deactivation Rate Constant

Total deactivation rate constants have been determined for N2+(B2Σu+) and the (A2Πu) and (B2Σu+) states of CO2+ with a number of quenchers. The energy specific total deactivation rate constant is compared to the total radiative lifetime of the excited species. A particular novelty of the technique is that it does not require a complete knowledge of the formation modes for the excited species. The results are compared with theoretical values obtained from the ion-induced dipole model. Individual deactivation rate constants are presented for N2+(B2Σu+) ions in the v = 0, 1, and 2 vibrational levels quenched by N2, O2, H2, and CO2; and for the(A2Πu) and (B2Σu+) states of CO2+ quenched byCO2, N2, O2, NO, and H2. Charge transfer is the most probable mode of deactivation except in the CO2+–H2 reactions where H-atom abstraction is more probable.

THE RATE OF REACTION OF ACTIVE NITROGEN WITH ETHANE, PROPANE, AND NEOPENTANE

1964 ◽  
Vol 42 (8) ◽  
pp. 1948-1956 ◽  
Author(s):  
W. E. Jones ◽  
C. A. Winkler
Keyword(s):  
Rate Constants ◽  
Reaction Times ◽  
Reactive Species ◽  
Hydrogen Atoms ◽  
Active Nitrogen ◽  
Probe Technique ◽  
Temperature Range ◽  
Excited Species ◽  
Rate Of Reaction ◽  
Dual Activation

The reactions of active nitrogen with ethane, propane, and neopentane have been studied over the temperature range 0 to 450 °C. A cobalt probe technique was used to stop the reactions after various reaction times. Second order rate constants have been calculated on the assumption that nitrogen atoms are the only reactive species in active nitrogen. Broken Arrhenius lines were obtained for both the ethane and neopentane reactions but this behavior was not observed with the propane reaction. The dual activation energies have been attributed to a mechanism involving initiation by both excited molecules and either nitrogen or hydrogen atoms. Methods are outlined by which an estimate has been made of the concentration of excited species assumed to be involved in the ethane reaction.

The reaction of hydrogen atoms with propylene

1971 ◽  
Vol 324 (1559) ◽  
pp. 433-446 ◽  
Keyword(s):  
Rate Constant ◽  
Rate Constants ◽  
Flow System ◽  
Primary Process ◽  
Absolute Rate ◽  
Hydrogen Atoms ◽  
Vibrationally Excited ◽  
Flow Rates ◽  
Detailed Mechanism ◽  
Excited Species

A detailed study has been made of the products of the reaction of hydrogen atoms with propylene. A discharge-flow system at 290±3 K was used. Total pressures in the range 4 to 16 Torr (550 to 2200 N m -2 ) of argon were used and the flow rates of hydrogen atoms and propylene ranged individually up to about 12 μ mol s -1 . As found by others the main products are methane, ethane, ethylene, propane and isobutane. Trivial amounts of 2,3-dimethylbutane, but no n-butane, were detected. A detailed mechanism accounting adequately for the reaction is proposed. It is confirmed that formation of the vibrationally excited species, i-C 3 H 7 *, is the predominant primary process. Novel processes which are shown to be important are H+i-C 3 H 7 * → CH 3 +C 2 H 5 and, C 3 H 8 * → CH 4 +C 2 H 4 . A number of rate constant ratios have been evaluated from the data and these allow calculation of absolute rate constants of some individual reactions. The agreement with previously reported values is, in most instances, good.

The reaction of hydrogen atoms with isobutene

1971 ◽  
Vol 324 (1559) ◽  
pp. 447-458 ◽  
Keyword(s):  
Rate Constants ◽  
Reaction System ◽  
Primary Process ◽  
Absolute Rate ◽  
Hydrogen Atoms ◽  
Vibrationally Excited ◽  
Flow Rates ◽  
Detailed Mechanism ◽  
Product Distributions ◽  
Excited Species

A detailed study has been made of the products of the reaction of hydrogen atoms with isobutene in a discharge flow reaction system at 290±3 K. Total pressures in the range 4 to 12 Torr (550 to 1650 N m -2 ) of argon were used and flow rates of hydrogen atoms and isobutene ranged individually up to about 10 μ mol s -1 . The main products were methane, ethane, ethylene, propane, propylene, isobutane and neopentane. A detailed mechanism accounting adequately for the observed product distributions and their dependence upon pressure and reactant mixture composition is proposed. The formation of the vibrationally excited species t-C 4 H 9 * is shown to be the predominant primary process. A number of rate constant ratios have been evaluated and absolute rate constants for some individual reactions have been estimated from the data. Some of the details of an earlier analogous study of the reaction of hydrogen atoms with propylene have been confirmed and some interesting correlations are indicated.

The formation, reaction and deactivation of O 2 ( 1 Ʃ + g )

1968 ◽  
Vol 308 (1492) ◽  
pp. 81-94 ◽  
Keyword(s):  
Energy Transfer ◽  
Molecular Oxygen ◽  
Transfer Process ◽  
Rate Constants ◽  
Atomic Oxygen ◽  
Energy Transfer Process ◽  
Formation Reaction ◽  
Upper Limit ◽  
Excited Species ◽  
Energy Pooling

The paper describes an investigation of the reaction with ozone and the deactivation of O 2 ( 1 Ʃ + g ). A flow technique was employed, and O 2 ( 1 Ʃ + g ) was produced photochemically by the sequence of reactions: O 2 + hv (λ=1470Å) → O( 1 D ) + O( 3 P ), (4) O( 1 D ) + O 2 ( 3 Ʃ - g ) → O 2 ( 1 Ʃ + g ) + O( 3 P ). (5) The advantages achieved by this method of generation of the excited species are discussed. Rate constants were obtained for the reaction of O 2 ( 1 Ʃ + g ) with ozone, and for its quenching by N 2 , and an estimate is made of the efficiency of wall deactivation. An upper limit is suggested for the quenching of O 2 ( 1 Ʃ + g ) by molecular oxygen. The results are compared with those of earlier investigations, and the comparison is used to calculate the rate constant of the ‘energy-pooling’ reaction: O 2 ( 1 ∆ g ) + O 2 ( 1 ∆ g ) → O 2 ( 1 Ʃ + g ) + O 2 ( 3 Ʃ - g ). (1) Measurement of the concentrations of O 2 ( 1 Ʃ + g ) and of atomic oxygen formed on photolysis allows the efficiency of the energy transfer process (5) to be assessed relative to the efficiency of quenching by O 2 , N 2 or Ar. The several rate constants measured or estimated are tabulated at the end of the paper in table 3.

Spectral band wings and rate constants of rotational relaxation as data source on molecular torques

1998 ◽  
Vol 94 (4) ◽  
pp. 627-642 ◽  
Author(s):  
A.P. KOUZOV
Keyword(s):  
Rate Constants ◽  
Spectral Band ◽  
Rotational Relaxation ◽  
Data Source
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