Experimental determination of the rate ...
Document type :
Article dans une revue scientifique: Article original
Permalink :
Title :
Experimental determination of the rate constants of the reactions of HO2 + DO and DO2+ DO2
Author(s) :
Assali, Mohamed [Auteur]
Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 [PC2A]
Rakovsky, Jozef [Auteur]
J. Heyrovský Institute of Physical Chemistry of the ASCR
Votava, Ondrej [Auteur]
J. Heyrovský Institute of Physical Chemistry of the ASCR
Fittschen, Christa [Auteur]
Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 [PC2A]
Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 [PC2A]
Rakovsky, Jozef [Auteur]
J. Heyrovský Institute of Physical Chemistry of the ASCR
Votava, Ondrej [Auteur]
J. Heyrovský Institute of Physical Chemistry of the ASCR
Fittschen, Christa [Auteur]
Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 [PC2A]
Journal title :
International Journal of Chemical Kinetics
Abbreviated title :
Int. J. Chem. Kinet.
Volume number :
52
Pages :
197-206
Publisher :
Wiley
Publication date :
2020-03-31
English keyword(s) :
DO2 radicals
HO2 radicals
kinetics
HO2 radicals
kinetics
HAL domain(s) :
Chimie/Chimie théorique et/ou physique
Physique [physics]/Physique [physics]
Physique [physics]/Physique [physics]/Chimie-Physique [physics.chem-ph]
Physique [physics]/Physique [physics]
Physique [physics]/Physique [physics]/Chimie-Physique [physics.chem-ph]
English abstract : [en]
The rate constants of the reactions of DO2 + HO2 (R1) and DO2 + DO2 (R2) have been determined by the simultaneous, selective, and quantitative measurement of HO2 and DO2 by continuous wave cavity ring‐down spectroscopy ...
Show more >The rate constants of the reactions of DO2 + HO2 (R1) and DO2 + DO2 (R2) have been determined by the simultaneous, selective, and quantitative measurement of HO2 and DO2 by continuous wave cavity ring‐down spectroscopy (cw‐CRDS) in the near infrared, coupled to a radical generation by laser photolysis. HO2 was generated by photolyzing Cl2 in the presence of CH3OH and O2. Low concentrations of DO2 were generated simultaneously by adding low concentrations of D2O to the reaction mixture, leading through isotopic exchange on tubing and reactor walls to formation of low concentrations of CH3OD and thus formation of DO2. Excess DO2 was generated by photolyzing Cl2 in the presence of CD3OD and O2, small concentrations of HO2 were always generated simultaneously by isotopic exchange between CD3OD and residual H2O. The rate constant k1 at 295 K was found to be pressure independent in the range 25–200 Torr helium, but increased with increasing D2O concentration k1 = (1.67 ± 0.03) × 10−12 × (1 + (8.2 ± 1.6) × 10−18 cm3 × [D2O] cm−3) cm3 s−1. The rate constant for the DO2 self‐reaction k2 has been measured under excess DO2 concentration, and the DO2 concentration has been determined by fitting the HO2 decays, now governed by their reaction with DO2, to the rate constant k1. A rate constant with insignificant pressure dependence was found: k2 = (4.1 ± 0.6) × 10−13 (1 + (2 ± 2) × 10−20 cm3 × [He] cm−3) cm3 s−1 as well as an increase of k2 with increasing D2O concentration was observed: k2 = (4.14 ± 0.02) × 10−13 × (1 + (6.5 ± 1.3) × 10−18 cm3 × [D2O] cm−3) cm3 s−1. The result for k2 is in excellent agreement with literature values, whereas this is the first determination of k1.Show less >
Show more >The rate constants of the reactions of DO2 + HO2 (R1) and DO2 + DO2 (R2) have been determined by the simultaneous, selective, and quantitative measurement of HO2 and DO2 by continuous wave cavity ring‐down spectroscopy (cw‐CRDS) in the near infrared, coupled to a radical generation by laser photolysis. HO2 was generated by photolyzing Cl2 in the presence of CH3OH and O2. Low concentrations of DO2 were generated simultaneously by adding low concentrations of D2O to the reaction mixture, leading through isotopic exchange on tubing and reactor walls to formation of low concentrations of CH3OD and thus formation of DO2. Excess DO2 was generated by photolyzing Cl2 in the presence of CD3OD and O2, small concentrations of HO2 were always generated simultaneously by isotopic exchange between CD3OD and residual H2O. The rate constant k1 at 295 K was found to be pressure independent in the range 25–200 Torr helium, but increased with increasing D2O concentration k1 = (1.67 ± 0.03) × 10−12 × (1 + (8.2 ± 1.6) × 10−18 cm3 × [D2O] cm−3) cm3 s−1. The rate constant for the DO2 self‐reaction k2 has been measured under excess DO2 concentration, and the DO2 concentration has been determined by fitting the HO2 decays, now governed by their reaction with DO2, to the rate constant k1. A rate constant with insignificant pressure dependence was found: k2 = (4.1 ± 0.6) × 10−13 (1 + (2 ± 2) × 10−20 cm3 × [He] cm−3) cm3 s−1 as well as an increase of k2 with increasing D2O concentration was observed: k2 = (4.14 ± 0.02) × 10−13 × (1 + (6.5 ± 1.3) × 10−18 cm3 × [D2O] cm−3) cm3 s−1. The result for k2 is in excellent agreement with literature values, whereas this is the first determination of k1.Show less >
Peer reviewed article :
Oui
Audience :
Internationale
Popular science :
Non
Administrative institution(s) :
Université de Lille
CNRS
CNRS
Research team(s) :
PhysicoChimie de l'Atmosphère (PCA)
Submission date :
2020-10-07T13:34:17Z
2020-11-06T14:02:54Z
2020-11-06T14:02:54Z
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