First Cavity Ring-Down Spectroscopy HO2 Measurements in a Large Photoreactor
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M. Djehiche
Abstract
The HO2 radical is one of the most important intermediate species in atmospheric chemistry. We report on the development of a new photoreactor with first in-situ measurement of HO2 radical photostationary concentrations using continuous wave cavity ring-down spectrometry (cw-CRDS). Characterization of the actinic photon flux was carried out by NO2 actinometry. Photolysis of Cl2/methanol mixtures in air under UV light allowed the measurement of HO2 photostationary concentrations of a few 1010 molecules cm-3 with an HO2 detection limit of 1.5 × 1010 molecules cm-3 at 6638.207 cm-1. The feasibility of HO2 direct measurement in a reaction chamber is demonstrated through the measurement of the HO2 overall loss at different pressures showing the importance of HO2 diffusion and wall loss in such low pressure quartz reactor. The rate coefficient for the HO2+HO2 reaction has been measured at 6.6, 24 and 118 mbar and found to be in good agreement with the recommended value.
© by Oldenbourg Wissenschaftsverlag, Lille, Germany
Articles in the same Issue
- Preface
- OH and NH Stretching Vibrational Relaxation of Liquid Ethanolamine
- Transient anisotropy in degenerate systems: A semi-classical approach
- First Cavity Ring-Down Spectroscopy HO2 Measurements in a Large Photoreactor
- Relaxation Dynamics of Electronically Excited C60− in o-Dichlorobenzene and Tetrahydrofuran Solution
- 3CH2 + O2: Kinetics and Product Channel Branching Ratios
- What Do We Know About the Iconic System CH3 + CH3 + M ↔ C2H6 + M?
- Thermochemistry and Kinetics for 2-Butanone-3yl Radical (CH3C(=O)CH•CH3) Reactions with O2
- Experimental and Modelling Study of the Unimolecular Thermal Decompostion of CHF3
- Combustion Chemistry of the Butane Isomers in Premixed Low-Pressure Flames
- Characterization of Rhodamine 6G Release in Electrospray Ionization by Means of Spatially Resolved Fluorescence Spectroscopy
- Femtosecond interferometry of molecular dynamics – the role of relative and absolute phase of two individual laser pulses
- Photodecarbonylation of Diphenylcyclopropenone – a Direct Pathway to Electronically Excited Diphenylacetylene?
- Yield of HO2 Radicals in the OH-Initiated Oxidation of SO2
- Pyrolysis of Ethyl Iodide as Hydrogen Atom Source: Kinetics and Mechanism in the Temperature Range 950–1200 K
- Reaction of OH and NO at Low Temperatures in the Presence of Water: the Role of Clusters
Articles in the same Issue
- Preface
- OH and NH Stretching Vibrational Relaxation of Liquid Ethanolamine
- Transient anisotropy in degenerate systems: A semi-classical approach
- First Cavity Ring-Down Spectroscopy HO2 Measurements in a Large Photoreactor
- Relaxation Dynamics of Electronically Excited C60− in o-Dichlorobenzene and Tetrahydrofuran Solution
- 3CH2 + O2: Kinetics and Product Channel Branching Ratios
- What Do We Know About the Iconic System CH3 + CH3 + M ↔ C2H6 + M?
- Thermochemistry and Kinetics for 2-Butanone-3yl Radical (CH3C(=O)CH•CH3) Reactions with O2
- Experimental and Modelling Study of the Unimolecular Thermal Decompostion of CHF3
- Combustion Chemistry of the Butane Isomers in Premixed Low-Pressure Flames
- Characterization of Rhodamine 6G Release in Electrospray Ionization by Means of Spatially Resolved Fluorescence Spectroscopy
- Femtosecond interferometry of molecular dynamics – the role of relative and absolute phase of two individual laser pulses
- Photodecarbonylation of Diphenylcyclopropenone – a Direct Pathway to Electronically Excited Diphenylacetylene?
- Yield of HO2 Radicals in the OH-Initiated Oxidation of SO2
- Pyrolysis of Ethyl Iodide as Hydrogen Atom Source: Kinetics and Mechanism in the Temperature Range 950–1200 K
- Reaction of OH and NO at Low Temperatures in the Presence of Water: the Role of Clusters
