Absolute absorption cross sections of the absorption spectrum of the 2nu1 band of the HO2 radical in the near-IR region were measured by continuous wave cavity ring-down spectroscopy (cw-CRDS) coupled to laser photolysis in the wavelength range 6604-6696 cm(-1) with a resolution better than 0.003 cm(-1). Absolute absorption cross sections were obtained by measuring the decay of the HO2 self-reaction, and they are given for the 100 most intense lines. The most important absorption feature in this wavelength range was found at 6638.20 cm(-1), exhibiting an absorption cross section of sigma = 2.72 x 10(-19) cm2 at 50 Torr He. Using this absorption line, we obtain a detection limit for the HO2 radical at 50 Torr of 6.5 x 10(10) cm(-3).
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http://dx.doi.org/10.1021/jp0703307 | DOI Listing |
Water Res
December 2024
Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing 400045, China. Electronic address:
The peroxone reaction, a promising alternative technology for water treatment, is traditionally hampered by its restricted pH operational range and suboptimal oxidant utilization. In this study, we introduced a novel amphoteric metal oxide (ZnO)-regulated peroxone system that transcended the pH limitations of conventional peroxone processes. Our innovative approach exploited the unique properties of ZnO to regulate the reaction pathway of the traditional O/HO (or peroxymonosulfate, PMS) processes, resulting in a 52.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstraße. 15, 04318 Leipzig, Germany.
The formation of methanesulfonic acid (MSA) from the dimethyl sulfide addition channel primarily proceeds the reaction of methylsulfonyloxy radicals (CHSO) with H-atom donors, other than HO radicals. In competition with it, thermal decomposition of CHSO results in SO generation. The MSA/SO ratio is driven by the temperature dependence of CHSO decomposition.
View Article and Find Full Text PDFJ Phys Chem A
December 2024
State Key Laboratory of Magnetic Resonance Spectroscopy and Imaging, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
The hydrogen abstraction reactions by small radicals from fuel molecules play an important role in the oxidation of fuels. However, experimental measurements and/or theoretical calculations of their rate constants under combustion conditions are very challenging due to their high reactivity. Machine learning offers a promising approach to predicting thermal rate constants.
View Article and Find Full Text PDFEnviron Sci Technol
December 2024
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.
3-Methylenebutane-1,2,4-triol and 3-methyltetrahydrofuran-2,4-diols, previously designated "C-alkene triols", were recently confirmed as in-particle isomerization products of isoprene-derived β-IEPOX isomers that are formed upon acid-driven uptake and partition back into the gas phase. In chamber experiments, we have systematically explored their gas phase oxidation by hydroxyl radical (OH) as a potential source of secondary organic aerosol (SOA). OH-initiated oxidation of both compounds in the presence of ammonium bisulfate aerosol resulted in substantial aerosol volume growth.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.
Criegee intermediates (CIs) play an important role in atmospheric chemistry as a transient source of the OH radical through their formation by the ozonolysis of unsaturated organic compounds. Here, we report thermally initiated formation of the smallest CI (CHOO) in the oxidation of ethane (CHCH) that may be relevant to combustion and flames. The SiO/SiC oxidation microreactor is heated to 1800 K and has a short residence time of ∼100 μs.
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