101
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Stone D, Whalley LK, Heard DE. Tropospheric OH and HO2 radicals: field measurements and model comparisons. Chem Soc Rev 2012; 41:6348-404. [DOI: 10.1039/c2cs35140d] [Citation(s) in RCA: 332] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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102
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Amedro D, Miyazaki K, Parker A, Schoemaecker C, Fittschen C. Atmospheric and kinetic studies of OH and HO2 by the FAGE technique. J Environ Sci (China) 2012; 24:78-86. [PMID: 22783617 DOI: 10.1016/s1001-0742(11)60723-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A new FAGE setup has recently been built at the University of Lille, France. It permits the quantification of OH and HO2 in the atmosphere with a detection limit of 3 x 105 molecules/(cm3 x min) for OH and 1 x 10(6) molecules/(cm3 x min) for HO2. Its coupling to a photolysis cell enables the measurement of the total reactivity of the hydroxyl radical in ambient air and kinetic studies in laboratory. Two configurations have been considered: one with the photolysis cell at 90 degrees to the FAGE nozzle, the other on line with the FAGE nozzle. The two configurations have been tested and validated by measuring the well known rate constants of OH with CH4, C3H8 and CO. The advantages and drawbacks of each configuration have been evaluated. The "on line" configuration limits losses and permits measurements over a larger reactivity range but is affected by OH formation from the laser beam striking the FAGE nozzle, thus limiting the ability to carry out energy dependence studies which can, in contrast, be successfully performed in the 90 degrees configuration.
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Affiliation(s)
- D Amedro
- Laboratoire PC2A, Université de Lille 1- Bâtiment C11, 59655 Villeneuve d'Ascq, France
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103
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Whalley L, Stone D, Heard D. New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Top Curr Chem (Cham) 2012; 339:55-95. [DOI: 10.1007/128_2012_359] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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104
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Dietrick SM, Pacheco AB, Phatak P, Stevens PS, Iyengar SS. Influence of Water on Anharmonicity, Stability, and Vibrational Energy Distribution of Hydrogen-Bonded Adducts in Atmospheric Reactions: Case Study of the OH + Isoprene Reaction Intermediate Using Ab Initio Molecular Dynamics. J Phys Chem A 2011; 116:399-414. [DOI: 10.1021/jp204511v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Scott M. Dietrick
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Alexander B. Pacheco
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Prasad Phatak
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Philip S. Stevens
- Department of Chemistry and Center for Research in Environmental Science, School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, United States
| | - Srinivasan S. Iyengar
- Departments of Chemistry and Physics, Indiana University, Bloomington, Indiana 47405, United States
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105
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Sakamoto Y, Tonokura K. Measurements of the Absorption Line Strength of Hydroperoxyl Radical in the ν3 Band using a Continuous Wave Quantum Cascade Laser. J Phys Chem A 2011; 116:215-22. [DOI: 10.1021/jp207477n] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yosuke Sakamoto
- Department of Chemical System Engineering, Graduate School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan,
| | - Kenichi Tonokura
- Department of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8563, Japan
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106
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Doppler limited rotational transitions of OH and SH radicals measured by continuous-wave terahertz photomixing. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2011.07.055] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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107
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Abstract
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.
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108
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Szabó E, Djehiche M, Riva M, Fittschen C, Coddeville P, Sarzyński D, Tomas A, Dóbé S. Atmospheric chemistry of 2,3-pentanedione: photolysis and reaction with OH radicals. J Phys Chem A 2011; 115:9160-8. [PMID: 21786774 DOI: 10.1021/jp205595c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The kinetics of the overall reaction between OH radicals and 2,3-pentanedione (1) were studied using both direct and relative kinetic methods at laboratory temperature. The low pressure fast discharge flow experiments coupled with resonance fluorescence detection of OH provided the direct rate coefficient of (2.25 ± 0.44) × 10(-12) cm(3) molecule(-1) s(-1). The relative-rate experiments were carried out both in a collapsible Teflon chamber and a Pyrex reactor in two laboratories using different reference reactions to provide the rate coefficients of 1.95 ± 0.27, 1.95 ± 0.34, and 2.06 ± 0.34, all given in 10(-12) cm(3) molecule(-1) s(-1). The recommended value is the nonweighted average of the four determinations: k(1) (300 K) = (2.09 ± 0.38) × 10(-12) cm(3) molecule(-1) s(-1), given with 2σ accuracy. Absorption cross sections for 2,3-pentanedione were determined: the spectrum is characterized by two wide absorption bands between 220 and 450 nm. Pulsed laser photolysis at 351 nm was used and the depletion of 2,3-pentanedione (2) was measured by GC to determine the photolysis quantum yield of Φ(2) = 0.11 ± 0.02(2σ) at 300 K and 1000 mbar synthetic air. An upper limit was estimated for the effective quantum yield of 2,3-pentanedione applying fluorescent lamps with peak wavelength of 312 nm. Relationships between molecular structure and OH reactivity, as well as the atmospheric fate of 2,3-pentanedione, have been discussed.
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Affiliation(s)
- Emese Szabó
- Université de Lille Nord de France, F-59000, Lille, France
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109
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Zhang S, Strekowski RS, Bosland L, Monod A, Zetzsch C. Kinetic study of the reaction of OH with CH3
I revisited. INT J CHEM KINET 2011. [DOI: 10.1002/kin.20583] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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110
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Farkas M, Illés Á, Petri B, Dóbé S. Direct rate constant for the reaction of OH radicals with the biofuel molecule ethyl levulinate. REACTION KINETICS MECHANISMS AND CATALYSIS 2011. [DOI: 10.1007/s11144-011-0364-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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111
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Long B, Tan XF, Long ZW, Wang YB, Ren DS, Zhang WJ. Theoretical Studies on Reactions of the Stabilized H2COO with HO2 and the HO2···H2O Complex. J Phys Chem A 2011; 115:6559-67. [DOI: 10.1021/jp200729q] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Bo Long
- College of Computer and Information Engineering, Guizhou University for Nationalities, Guiyang, China 550025
| | - Xing-feng Tan
- College of Photo-Electronics, Chongqing University of Posts and Telecommunications, Chongqing, China 400065
| | | | | | - Da-sen Ren
- College of Computer and Information Engineering, Guizhou University for Nationalities, Guiyang, China 550025
| | - Wei-jun Zhang
- Laboratory of Environment Spectroscopy, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei, China 230031
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112
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Affiliation(s)
- Thorsten Hoffmann
- Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University, Mainz, Germany
| | - Ru-Jin Huang
- Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University, Mainz, Germany
| | - Markus Kalberer
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
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113
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114
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Zhao W, Wysocki G, Chen W, Fertein E, Le Coq D, Petitprez D, Zhang W. Sensitive and selective detection of OH radicals using Faraday rotation spectroscopy at 2.8 µm. OPTICS EXPRESS 2011; 19:2493-2501. [PMID: 21369069 DOI: 10.1364/oe.19.002493] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report on the development of a Faraday rotation spectroscopy (FRS) instrument using a DFB diode laser operating at 2.8 µm for the hydroxyl (OH) free radical detection. The highest absorption line intensity and the largest gJ value make the Q (1.5) double lines of the 2Π3/2 state (υ = 1 ← 0) at 2.8 µm clearly the best choice for sensitive detection in the infrared region by FRS. The prototype instrument shows shot-noise dominated performance and, with an active optical pathlength of only 25 cm and a lock-in time constant of 100 ms, achieves a 1σ detection limit of 8.2 × 10(8) OH radicals/cm3.
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Affiliation(s)
- Weixiong Zhao
- Laboratoire de Physicochimie de l’Atmosphère, Université du Littoral Côte d’Opale, 189A Av Maurice Schumann, 59140 Dunkerque, France
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115
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Waring C, King KL, Bagot PAJ, Costen ML, McKendrick KG. Collision dynamics and reactive uptake of OH radicals at liquid surfaces of atmospheric interest. Phys Chem Chem Phys 2011; 13:8457-69. [DOI: 10.1039/c0cp02734k] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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116
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Zhang S, Strekowski R, Bosland L, Monod A, Zetzsch C. Kinetic study of the reaction of OH with CH2I2. Phys Chem Chem Phys 2011; 13:11671-7. [DOI: 10.1039/c1cp20885c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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117
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da Silva G. Kinetics and Mechanism of the Glyoxal + HO2 Reaction: Conversion of HO2 to OH by Carbonyls. J Phys Chem A 2010; 115:291-7. [DOI: 10.1021/jp108358y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriel da Silva
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville 3010, Victoria, Australia
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118
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Kuwata KT, Hermes MR, Carlson MJ, Zogg CK. Computational studies of the isomerization and hydration reactions of acetaldehyde oxide and methyl vinyl carbonyl oxide. J Phys Chem A 2010; 114:9192-204. [PMID: 20701322 DOI: 10.1021/jp105358v] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Alkene ozonolysis is a major source of hydroxyl radical (*OH), the most important oxidant in the troposphere. Previous experimental and computational work suggests that for many alkenes the measured *OH yields should be attributed to the combined impact of both chemically activated and thermalized syn-alkyl Criegee intermediates (CIs), even though the thermalized CI should be susceptible to trapping by molecules such as water. We have used RRKM/master equation and variational transition state theory calculations to quantify the competition between unimolecular isomerization and bimolecular hydration reactions for the syn and anti acetaldehyde oxide formed in trans-2-butene ozonolysis and for the CIs formed in isoprene ozonolysis possessing syn-methyl groups. Statistical rate theory calculations were based on quantum chemical data provided by the B3LYP, QCISD, and multicoefficient G3 methods, and thermal rate constants were corrected for tunneling effects using the Eckart method. At tropospheric temperatures and pressures, all thermalized CIs with syn-methyl groups are predicted to undergo 1,4-hydrogen shifts from 2 to 8 orders of magnitude faster than they react with water monomer at its saturation number density. For thermalized anti acetaldehyde oxide, the rates of dioxirane formation and hydration should be comparable.
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Affiliation(s)
- Keith T Kuwata
- Department of Chemistry, Macalester College, Saint Paul, Minnesota 55105-1899, USA.
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119
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White IR, Martin D, Muñoz MP, Petersson FK, Henshaw SJ, Nickless G, Lloyd-Jones GC, Clemitshaw KC, Shallcross DE. Use of reactive tracers to determine ambient OH radical concentrations: application within the indoor environment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:6269-6274. [PMID: 20704225 DOI: 10.1021/es901699a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The hydroxyl radical (OH) plays a key role in determining indoor air quality. However, its highly reactive nature and low concentration indoors impede direct analysis. This paper describes the techniques used to indirectly quantify indoor OH, including the development of a new method based on the instantaneous release of chemical tracers into the air. This method was used to detect ambient OH in two indoor seminar rooms following tracer detection by gas chromatography-mass spectrometry (GCMS). The results from these tests add to the small number of experiments that have measured indoor OH which are discussed with regard to future directions within air quality research.
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Affiliation(s)
- Iain R White
- School of Chemistry, Bristol University, Bristol BS8 1TS, UK
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120
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Lu K, Zhang Y, Su H, Brauers T, Chou CC, Hofzumahaus A, Liu SC, Kita K, Kondo Y, Shao M, Wahner A, Wang J, Wang X, Zhu T. Oxidant (O3+ NO2) production processes and formation regimes in Beijing. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jd012714] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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121
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Fiddler MN, Begashaw I, Mickens MA, Collingwood MS, Assefa Z, Bililign S. Laser spectroscopy for atmospheric and environmental sensing. SENSORS 2009; 9:10447-512. [PMID: 22303184 PMCID: PMC3267232 DOI: 10.3390/s91210447] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 12/02/2009] [Indexed: 12/12/2022]
Abstract
Lasers and laser spectroscopic techniques have been extensively used in several applications since their advent, and the subject has been reviewed extensively in the last several decades. This review is focused on three areas of laser spectroscopic applications in atmospheric and environmental sensing; namely laser-induced fluorescence (LIF), cavity ring-down spectroscopy (CRDS), and photoluminescence (PL) techniques used in the detection of solids, liquids, aerosols, trace gases, and volatile organic compounds (VOCs).
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Affiliation(s)
- Marc N. Fiddler
- NOAA-ISET Center, North Carolina A&T State University, 1601 E Market Street Greensboro, NC 27411, USA; E-Mail:
| | - Israel Begashaw
- Department of Physics, North Carolina A&T State University, Greensboro, 1601 E Market Street, Marteena Hall, Greensboro, NC 27411, USA; E-Mail:
| | - Matthew A. Mickens
- Department of Chemistry, North Carolina A&T State University, 1601 E Market Street, New Science Building, Greensboro, NC 27411, USA; E-Mail:
- Energy & Environmental Systems Program, North Carolina A&T State University, 1601 E Market Street, Greensboro, NC 27411, USA; E-Mail:
| | - Michael S. Collingwood
- Energy & Environmental Systems Program, North Carolina A&T State University, 1601 E Market Street, Greensboro, NC 27411, USA; E-Mail:
| | - Zerihun Assefa
- NOAA-ISET Center, North Carolina A&T State University, 1601 E Market Street Greensboro, NC 27411, USA; E-Mail:
- Department of Chemistry, North Carolina A&T State University, 1601 E Market Street, New Science Building, Greensboro, NC 27411, USA; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (Z.A.); (S.B.); Tel.: +1-336-285-2328/2255; Fax: +1-336-256-2542/ 334-7124
| | - Solomon Bililign
- NOAA-ISET Center, North Carolina A&T State University, 1601 E Market Street Greensboro, NC 27411, USA; E-Mail:
- Department of Physics, North Carolina A&T State University, Greensboro, 1601 E Market Street, Marteena Hall, Greensboro, NC 27411, USA; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (Z.A.); (S.B.); Tel.: +1-336-285-2328/2255; Fax: +1-336-256-2542/ 334-7124
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122
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Hofzumahaus A, Rohrer F, Lu K, Bohn B, Brauers T, Chang CC, Fuchs H, Holland F, Kita K, Kondo Y, Li X, Lou S, Shao M, Zeng L, Wahner A, Zhang Y. Amplified Trace Gas Removal in the Troposphere. Science 2009; 324:1702-4. [DOI: 10.1126/science.1164566] [Citation(s) in RCA: 465] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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123
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Carr S, Heard DE, Blitz MA. Comment on "Atmospheric Hydroxyl Radical Production from Electronically Excited NO
2
and H
2
O". Science 2009; 324:336; author reply 336. [DOI: 10.1126/science.1166669] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Scott Carr
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
- National Centre for Atmospheric Science, School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | - Dwayne E. Heard
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
- National Centre for Atmospheric Science, School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | - Mark A. Blitz
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
- National Centre for Atmospheric Science, School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
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124
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Gross S, Iannone R, Xiao S, Bertram AK. Reactive uptake studies of NO3 and N2O5 on alkenoic acid, alkanoate, and polyalcohol substrates to probe nighttime aerosol chemistry. Phys Chem Chem Phys 2009; 11:7792-803. [DOI: 10.1039/b904741g] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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125
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Fuchs H, Holland F, Hofzumahaus A. Measurement of tropospheric RO2 and HO2 radicals by a laser-induced fluorescence instrument. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:084104. [PMID: 19044365 DOI: 10.1063/1.2968712] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A new method (ROxLIF) for the measurement of atmospheric peroxy radicals (HO(2) and RO(2)) was developed using a two-step chemical conversion scheme and laser-induced fluorescence (LIF) for radical detection. Ambient air is sampled into a differentially pumped flow reactor, in which atmospheric RO(x) radicals (=RO(2)+RO+HO(2)+OH) are chemically converted to HO(2) by a large excess of NO and CO at reduced pressures (ROx mode). When only CO is added as a reagent, the sum of atmospheric HO(2)+OH is converted to HO(2) (HOx mode). At the reactor outlet, part of the air flow is transferred into a low-pressure detection chamber, where the HO(2) is further converted by reaction with NO to OH, which is then detected with high sensitivity by LIF at 308 nm. The ROxLIF technique has been implemented in an existing LIF instrument that is also capable of measuring atmospheric OH. From the concurrent measurements of RO(x), HO(x) and OH, concentrations of HO(2) and RO(2) can be determined. The system is calibrated using the quantitative photolysis of water vapor at 185 nm as a radical source. Addition of CO or hydrocarbons to the calibration gas yields well-defined concentrations of HO(2) or RO(2), respectively, providing an estimated accuracy for the calibration of about 20%. The ROxLIF technique is extremely sensitive and has detection limits (signal-to-noise ratio=2) of about 0.1 pptv of HO(2) or RO(2) at a time resolution of 1 min. The paper describes the technique and its calibration, discusses the chemistry in the conversion reactor and possible interferences, and gives an example of ambient air measurements to demonstrate the performance of the new technique.
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Affiliation(s)
- Hendrik Fuchs
- Forschungszentrum Julich GmbH, Institut fur Chemie und Dynamik der Geosphare 2, 52425 Julich, Germany
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126
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In-situ Calibration of the Hydroperoxyl Radical Using an Immobilized TiO 2Photocatalyst in the Atmosphere. B KOREAN CHEM SOC 2008. [DOI: 10.5012/bkcs.2008.29.4.785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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127
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The Study of Dynamically Averaged Vibrational Spectroscopy of Atmospherically Relevant Clusters Using Ab Initio Molecular Dynamics in Conjunction with Quantum Wavepackets. ADVANCES IN QUANTUM CHEMISTRY 2008. [DOI: 10.1016/s0065-3276(07)00216-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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128
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Liu B, Wang HX. Determination of atmospheric hydroxyl radical by HPLC coupled with electrochemical detection. J Environ Sci (China) 2008; 20:28-32. [PMID: 18572518 DOI: 10.1016/s1001-0742(08)60003-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The hydroxyl radical (*OH) plays a central role in the oxidation and removal of many atmospheric compounds. Measurement of atmospheric *OH is very difficult because of its high reactivity and low atmospheric abundance. In this article, a simple and highly sensitive method, high performance liquid chromatography coupled with coulometric detection (HPLC-CD), was developed to determine *OH indirectly by determining its reaction products with salicylic acid (SAL), 2,3-dihydroxybenzoic acid (2,3-DHBA), and 2,5-dihydroxybenzoic acid (2,5-DHBA). Under the optimum conditions for its determination, 2,3-DHBA and 2,5-DHBA could be well separated and the detection limits for 2,3-DHBA were 3 x 10(-10) mol/L and for 2,5-DHBA were 1.5 x 10(-10) mol/L, which were lower than most previous reports. This method was also applied to measure atmospheric hydroxyl radical levels and demonstrated the feasibility in clean and polluted air.
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Affiliation(s)
- Bin Liu
- College of Environmental Sciences, Peking University, Beijing 100871, China.
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129
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Carr SA, Baeza-Romero MT, Blitz MA, Price BJS, Seakins PW. Ketone photolysis in the presence of oxygen: A useful source of OH for flash photolysis kinetics experiments. INT J CHEM KINET 2008. [DOI: 10.1002/kin.20330] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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130
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D'Andrea TM, Zhang X, Jochnowitz EB, Lindeman TG, Simpson CJSM, David DE, Curtiss TJ, Morris JR, Ellison GB. Oxidation of Organic Films by Beams of Hydroxyl Radicals. J Phys Chem B 2007; 112:535-44. [DOI: 10.1021/jp7096108] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Timothy M. D'Andrea
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - Xu Zhang
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - Evan B. Jochnowitz
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - T. G. Lindeman
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - C. J. S. M. Simpson
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - Donald E. David
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - Thomas J. Curtiss
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - John R. Morris
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
| | - G. Barney Ellison
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 19, CH-4056 Basel, Switzerland, Department of Chemistry, Colorado College, Colorado Springs, Colorado 80903-3298, Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom,
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131
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Alongi KS, Dibble TS, Shields GC, Kirschner KN. Exploration of the potential energy surfaces, prediction of atmospheric concentrations, and prediction of vibrational spectra for the HO2...(H2O)n (n = 1-2) hydrogen bonded complexes. J Phys Chem A 2007; 110:3686-91. [PMID: 16526652 PMCID: PMC2548419 DOI: 10.1021/jp057165k] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The hydroperoxy radical (HO2) plays a critical role in Earth's atmospheric chemistry as a component of many important reactions. The self-reaction of hydroperoxy radicals in the gas phase is strongly affected by the presence of water vapor. In this work, we explore the potential energy surfaces of hydroperoxy radicals hydrogen bonded to one or two water molecules, and predict atmospheric concentrations and vibrational spectra of these complexes. We predict that when the HO2 concentration is on the order of 10(8) molecules x cm(-3) at 298 K, that the number of HO2...H2O complexes is on the order of 10(7) molecules x cm(-3) and the number of HO2...(H2O)2 complexes is on the order of 10(6) molecules x cm(-3). Using the computed abundance of HO2...H2O, we predict that, at 298 K, the bimolecular rate constant for HO2...H2O + HO2 is about 10 times that for HO2 + HO2.
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Affiliation(s)
- Kristin S Alongi
- Department of Chemistry, Hamilton College, Clinton, New York 13323, USA
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132
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Kuwata KT, Valin LC, Converse AD. Quantum chemical and master equation studies of the methyl vinyl carbonyl oxides formed in isoprene ozonolysis. J Phys Chem A 2007; 109:10710-25. [PMID: 16863120 DOI: 10.1021/jp054346d] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methyl vinyl carbonyl oxide is an important intermediate in the reaction of isoprene and ozone and may be responsible for most of the (*)OH formed in isoprene ozonolysis. We use CBS-QB3 calculations and RRKM/master equation simulations to characterize all the pathways leading to the formation of this species, all the interconversions among its four possible conformers, and all of its irreversible isomerizations. Our calculations, like previous studies, predict (*)OH yields consistent with experiment if thermalized syn-methyl carbonyl oxides form (*)OH quantitatively. Natural bond order analysis reveals that the vinyl group weakens the C=O bond of the carbonyl oxide, making rotation about this bond accessible to this chemically activated intermediate. The vinyl group also allows one conformer of the carbonyl oxide to undergo electrocyclization to form a dioxole, a species not previously considered in the literature. Dioxole formation, which has a CBS-QB3 reaction barrier of 13.9 kcal/mol, is predicted to be favored over vinyl hydroperoxide formation, dioxirane formation, and collisional stabilization. Our calculations also predict that two dioxole derivatives, 1,2-epoxy-3-butanone and 3-oxobutanal, should be major products of isoprene ozonolysis.
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Affiliation(s)
- Keith T Kuwata
- Department of Chemistry, Macalester College, Saint Paul, Minnesota 55105-1899, USA.
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133
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Kanaya Y, Cao R, Kato S, Miyakawa Y, Kajii Y, Tanimoto H, Yokouchi Y, Mochida M, Kawamura K, Akimoto H. Chemistry of OH and HO2radicals observed at Rishiri Island, Japan, in September 2003: Missing daytime sink of HO2and positive nighttime correlations with monoterpenes. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007987] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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134
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Arnold SR, Methven J, Evans MJ, Chipperfield MP, Lewis AC, Hopkins JR, McQuaid JB, Watson N, Purvis RM, Lee JD, Atlas EL, Blake DR, Rappenglück B. Statistical inference of OH concentrations and air mass dilution rates from successive observations of nonmethane hydrocarbons in single air masses. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007594] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- S. R. Arnold
- Institute for Atmospheric Science, School of Earth and Environment; University of Leeds; Leeds UK
| | - J. Methven
- Department of Meteorology; University of Reading; Reading UK
| | - M. J. Evans
- Institute for Atmospheric Science, School of Earth and Environment; University of Leeds; Leeds UK
| | - M. P. Chipperfield
- Institute for Atmospheric Science, School of Earth and Environment; University of Leeds; Leeds UK
| | - A. C. Lewis
- Department of Chemistry; University of York; York UK
| | - J. R. Hopkins
- Department of Chemistry; University of York; York UK
| | - J. B. McQuaid
- Institute for Atmospheric Science, School of Earth and Environment; University of Leeds; Leeds UK
| | - N. Watson
- Department of Chemistry; University of York; York UK
| | - R. M. Purvis
- Department of Chemistry; University of York; York UK
| | - J. D. Lee
- Department of Chemistry; University of York; York UK
| | - E. L. Atlas
- Division of Marine and Atmospheric Chemistry, Rosenstiel School of Marine and Atmospheric Science; University of Miami; Miami Florida USA
| | - D. R. Blake
- Department of Chemistry; University of California; Irvine California USA
| | - B. Rappenglück
- Institute of Meteorology and Climate Research; Forschungszentrum Karlsruhe; Garmisch-Partenkirchen Germany
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135
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Heard DE. Atmospheric field measurements of the hydroxyl radical using laser-induced fluorescence spectroscopy. Annu Rev Phys Chem 2007; 57:191-216. [PMID: 16599809 DOI: 10.1146/annurev.physchem.57.032905.104516] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The hydroxyl radical, OH, is the most important cleansing agent in the Earth's atmosphere, removing the majority of trace gases by oxidation, including greenhouse gases and CFC replacements. It is intimately involved in the chemistry that generates photochemical smog, which includes many substances harmful to health, such as ozone and particulate matter. In this review, the technique of laser-induced fluorescence for the detection of OH in the atmosphere is described, using as an example the fluorescence assay by gas expansion (FAGE) instrument developed at the University of Leeds. The comparison of measured OH concentrations at a given field site with those calculated by an atmospheric model, which is a mathematical representation of the underlying chemistry, provides one of the best methods to test whether the key chemical and physical processes are understood. Examples are given for field measurements made in clean and polluted environments.
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Affiliation(s)
- Dwayne E Heard
- School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom.
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136
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Robinson AL, Donahue NM, Shrivastava MK, Weitkamp EA, Sage AM, Grieshop AP, Lane TE, Pierce JR, Pandis SN. Rethinking Organic Aerosols: Semivolatile Emissions and Photochemical Aging. Science 2007; 315:1259-62. [PMID: 17332409 DOI: 10.1126/science.1133061] [Citation(s) in RCA: 506] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Most primary organic-particulate emissions are semivolatile; thus, they partially evaporate with atmospheric dilution, creating substantial amounts of low-volatility gas-phase material. Laboratory experiments show that photo-oxidation of diesel emissions rapidly generates organic aerosol, greatly exceeding the contribution from known secondary organic-aerosol precursors. We attribute this unexplained secondary organic-aerosol production to the oxidation of low-volatility gas-phase species. Accounting for partitioning and photochemical processing of primary emissions creates a more regionally distributed aerosol and brings model predictions into better agreement with observations. Controlling organic particulate-matter concentrations will require substantial changes in the approaches that are currently used to measure and regulate emissions.
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Affiliation(s)
- Allen L Robinson
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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137
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Baeza-Romero MT, Glowacki DR, Blitz MA, Heard DE, Pilling MJ, Rickard AR, Seakins PW. A combined experimental and theoretical study of the reaction between methylglyoxal and OH/OD radical: OH regeneration. Phys Chem Chem Phys 2007; 9:4114-28. [PMID: 17687462 DOI: 10.1039/b702916k] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Experimental studies have been conducted to determine the rate coefficient and mechanism of the reaction between methylglyoxal (CH(3)COCHO, MGLY) and the OH radical over a wide range of temperatures (233-500 K) and pressures (5-300 Torr). The rate coefficient is pressure independent with the following temperature dependence: k(3)(T) = (1.83 +/- 0.48) x 10(-12) exp((560 +/- 70)/T) cm(3) molecule(-1) s(-1) (95% uncertainties). Addition of O(2) to the system leads to recycling of OH. The mechanism was investigated by varying the experimental conditions ([O(2)], [MGLY], temperature and pressure), and by modelling based on a G3X potential energy surface, rovibrational prior distribution calculations and master equation RRKM calculations. The mechanism can be described as follows: Addition of oxygen to the system shows that process (4) is fast and that CH(3)COCO completely dissociates. The acetyl radical formed from reaction (4) reacts with oxygen to regenerate OH radicals (5a). However, a significant fraction of acetyl radical formed by reaction (R4) is sufficiently energised to dissociate further to CH(3) + CO (R4b). Little or no pressure quenching of reaction (R4b) was observed. The rate coefficient for OD + MGLY was measured as k(9)(T) = (9.4 +/- 2.4) x 10(-13) exp((780 +/- 70)/T) cm(3) molecule(-1) s(-1) over the temperature range 233-500 K. The reaction shows a noticeable inverse (k(H)/k(D) < 1) kinetic isotope effect below room temperature and a slight normal kinetic isotope effect (k(H)/k(D) > 1) at high temperature. The potential atmospheric implications of this work are discussed.
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138
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Allodi MA, Dunn ME, Livada J, Kirschner KN, Shields GC. Do Hydroxyl Radical−Water Clusters, OH(H2O)n, n = 1−5, Exist in the Atmosphere? J Phys Chem A 2006; 110:13283-9. [PMID: 17149847 DOI: 10.1021/jp064468l] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
It has been speculated that the presence of OH(H2O)n clusters in the troposphere could have significant effects on the solar absorption balance and the reactivity of the hydroxyl radical. We have used the G3 and G3B3 model chemistries to model the structures and predict the frequencies of hydroxyl radical/water clusters containing one to five water molecules. The reaction between hydroxyl radical clusters and methane was examined as a function of water cluster size to gain an understanding of how cluster size affects the hydroxyl radical reactivity.
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Affiliation(s)
- Marco A Allodi
- Department of Chemistry, Hamilton College, Clinton, New York 13323, USA
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139
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Torrent-Sucarrat M, Anglada JM. On the Gas Phase Hydrogen Bond Complexes between Formic Acid and Hydroperoxyl Radical. A Theoretical Study. J Phys Chem A 2006; 110:9718-26. [PMID: 16884204 DOI: 10.1021/jp060884u] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We present a systematic study on the gas-phase hydrogen-bonded complexes formed between formic acid and hydroperoxyl radical, which has been carried out by using B3LYP and CCSD(T) theoretical approaches in connection with the 6-311+G(2df,2p) basis set. For all complexes we have employed the AIM theory by Bader and the NBO partition scheme by Weinhold to analyze the bonding features. We have found 17 stationary points, and 11 of them present a cyclic structure. Their computed stabilities vary from 0.3 to 11.3 kcal/mol, depending on several factors, such as involvement in the hydrogen bond interaction, the geometrical constraints, and the possible concurrence of further effects such as resonance-assisted hydrogen bonds or inductive effects. In addition, three stationary points correspond to transition structures involving a double proton-transfer process whose features are also analyzed.
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Affiliation(s)
- M Torrent-Sucarrat
- Institut de Química Computacional and Departament de Química, Universitat de Girona, E-17071 Girona, Catalonia, Spain
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140
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141
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Rohrer F, Berresheim H. Strong correlation between levels of tropospheric hydroxyl radicals and solar ultraviolet radiation. Nature 2006; 442:184-7. [PMID: 16838018 DOI: 10.1038/nature04924] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Accepted: 05/19/2006] [Indexed: 11/09/2022]
Abstract
The most important chemical cleaning agent of the atmosphere is the hydroxyl radical, OH. It determines the oxidizing power of the atmosphere, and thereby controls the removal of nearly all gaseous atmospheric pollutants. The atmospheric supply of OH is limited, however, and could be overcome by consumption due to increasing pollution and climate change, with detrimental feedback effects. To date, the high variability of OH concentrations has prevented the use of local observations to monitor possible trends in the concentration of this species. Here we present and analyse long-term measurements of atmospheric OH concentrations, which were taken between 1999 and 2003 at the Meteorological Observatory Hohenpeissenberg in southern Germany. We find that the concentration of OH can be described by a surprisingly linear dependence on solar ultraviolet radiation throughout the measurement period, despite the fact that OH concentrations are influenced by thousands of reactants. A detailed numerical model of atmospheric reactions and measured trace gas concentrations indicates that the observed correlation results from compensations between individual processes affecting OH, but that a full understanding of these interactions may not be possible on the basis of our current knowledge of atmospheric chemistry. As a consequence of the stable relationship between OH concentrations and ultraviolet radiation that we observe, we infer that there is no long-term trend in the level of OH in the Hohenpeissenberg data set.
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Affiliation(s)
- Franz Rohrer
- Forschungszentrum Jülich, Institut ICG-II: Troposphäre, Jülich 52425, Germany.
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142
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Olson JR, Crawford JH, Chen G, Brune WH, Faloona IC, Tan D, Harder H, Martinez M. A reevaluation of airborne HOxobservations from NASA field campaigns. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006617] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jennifer R. Olson
- Atmospheric Sciences Division, Langley Research Center; NASA; Hampton Virginia USA
| | - James H. Crawford
- Atmospheric Sciences Division, Langley Research Center; NASA; Hampton Virginia USA
| | - Gao Chen
- Atmospheric Sciences Division, Langley Research Center; NASA; Hampton Virginia USA
| | - William H. Brune
- Department of Meteorology; Pennsylvania State University; University Park Pennsylvania USA
| | - Ian C. Faloona
- Department of Land, Air and Water Resources; University of California; Davis California USA
| | - David Tan
- School of Earth and Atmospheric Sciences; Georgia Institute of Technology; Atlanta Georgia USA
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143
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Kanaya Y, Akimoto H. Gating a channel photomultiplier with a fast high-voltage switch: reduction of afterpulse rates in a laser-induced fluorescence instrument for measurement of atmospheric OH radical concentrations. APPLIED OPTICS 2006; 45:1254-9. [PMID: 16523790 DOI: 10.1364/ao.45.001254] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
By employing a commercially available high-voltage switch in a time-gating circuit to drive a channel photomultiplier (CPM), the afterpulse rates are significantly reduced in the time window to collect fluorescence >200 ns after the pulsed laser excitation. The CPM, kept deactivated under normal conditions (normally off), is turned on immediately after the passage of the laser pulse by shifting the voltage applied to the photocathode by 150 V to collect the fluorescence. When the detection system is used as part of a laser-induced fluorescence instrument to measure atmospheric OH radicals with the photon-counting method, the background signal is reduced by more than a factor of 10 as compared with our previous case where a conventional dynode-gated photomultiplier tube (PMT) is used, while the sensitivity toward the fluorescence is almost unchanged. A detection limit as low as 2 x 10(5) radicals cm-3 or 0.008 parts per trillion by volume is achieved for OH, with an integration time of 1 min and a signal-to-noise ratio of 2, enabling sensitive detection of the important radical in the atmosphere. This system is a superior choice with higher sensitivity and cost effectiveness as compared with the gated PMITs utilizing a microchannel plate as an electron multiplier, and could also be used effectively in light detection and ranging (lidar) instruments, where a delayed scattering signal would be efficiently discriminated from afterpulses.
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Affiliation(s)
- Yugo Kanaya
- Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohoma, Kanagawa 236-0001, Japan.
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144
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Robinson AL, Donahue NM, Rogge WF. Photochemical oxidation and changes in molecular composition of organic aerosol in the regional context. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006265] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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145
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Green TJ, Reeves CE, Fleming ZL, Brough N, Rickard AR, Bandy BJ, Monks PS, Penkett SA. An improved dual channel PERCA instrument for atmospheric measurements of peroxy radicals. ACTA ACUST UNITED AC 2006; 8:530-6. [PMID: 16688354 DOI: 10.1039/b514630e] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper describes a new dual-channel PEroxy RadiCal Amplification (PERCA) instrument, which has been designed to improve the time resolution and signal to noise and to reduce the interference caused by variations in ambient ozone concentrations. The instrument was run at the Weybourne Atmospheric Observatory (WAO), North Norfolk, during WAOWEX (Weybourne Atmospheric Observatory Winter Experiment) in January/February 2002 and INSPECTRO (Influence of clouds on the spectral actinic flux in the lower troposphere) in September 2002. The performance of the instrument is assessed and compared to that of a single channel instrument. In particular, it is shown how the precision is greatly improved in fluctuating background ozone conditions. In addition the improved time response of the instrument allows changes in peroxy radical concentrations to be related to rapid changes in nitric oxide concentrations and the ozone photolysis frequency, j(O(1)D).
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Affiliation(s)
- Timothy J Green
- School of Environmental Science, University of East Anglia, University Plain, Norwich, UKNR4 7TJ
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146
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Iyengar SS. Dynamical effects on vibrational and electronic spectra of hydroperoxyl radical water clusters. J Chem Phys 2005; 123:084310. [PMID: 16164294 DOI: 10.1063/1.2006674] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We have carried out ab initio molecular-dynamics studies on hydroperoxyl water clusters. Our studies are complemented by optimization, frequency, and excited-state calculations. The three main results we obtained are (a) the dynamically averaged energy gap between the highest-occupied molecular orbital and the lowest-unoccupied molecular orbital monotonically decreases as the number of water molecules is increased in a hydroperoxyl water cluster system, (b) the dynamical averaging of the potential-energy surface at finite temperature broadens the electronic excitation spectrum and changes the infrared spectrum in nontrivial ways, and (c) the structural analysis of our dynamics simulation indicates that the oxygen-oxygen distance in a solvated hydroperoxyl-water cluster is very similar to that found in protonated water clusters (Zundel: H5O2+) inspite of the fact that the latter possesses a positive charge and the hydroperoxyl-water cluster does not. Dynamical charge analysis and the weak acidity of HO2 are used to justify this result.
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Affiliation(s)
- Srinivasan S Iyengar
- Department of Chemistry and Department of Physics, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, USA.
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147
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Greenslade ME, Lester MI, Radenović DC, van Roij AJA, Parker DH. (2+1) Resonance-enhanced ionization spectroscopy of a state-selected beam of OH radicals. J Chem Phys 2005; 123:074309. [PMID: 16229572 DOI: 10.1063/1.1997132] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A state-selected beam of hydroxyl radicals is generated using a pulsed discharge source and hexapole field. The OH radicals are characterized by resonance-enhanced multiphoton ionization (REMPI) spectroscopy via the nested D 2Sigma- and 3 2Sigma- Rydberg states. Simplified spectra are observed from the selected |MJ|=3/2 component of the upper Lambda-doublet level of the lowest rotational state (J=32) in ground (v"=0) and excited (v"=1-3) vibrational levels of the OH X 2Pi3/2 state. Two-photon transitions are observed to the D 2Sigma-(v'=0-3) and 3 2Sigma-(v'=0,1) vibronic levels, extending previous studies to higher vibrational levels of the Rydberg states. Spectroscopic constants are derived for the Rydberg states and compared with prior experimental studies. Complementary first-principle theoretical studies of the properties of the D 2Sigma- and 3 2Sigma- Rydberg states [see M. P. J. van der Loo and G. C. Groenenboom, J. Chem. Phys. 123, 074310 (2005), following paper] are used to interpret the experimental findings and examine the utility of the (2+1) REMPI scheme for sensitive detection of OH radicals.
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Affiliation(s)
- Margaret E Greenslade
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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148
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Kuwata KT, Hasson AS, Dickinson RV, Petersen EB, Valin LC. Quantum Chemical and Master Equation Simulations of the Oxidation and Isomerization of Vinoxy Radicals. J Phys Chem A 2005; 109:2514-24. [PMID: 16833553 DOI: 10.1021/jp047299i] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The vinoxy radical, a common intermediate in gas-phase alkene ozonolysis, reacts with O2 to form a chemically activated alpha-oxoperoxy species. We report CBS-QB3 energetics for O2 addition to the parent (*CH2CHO, 1a), 1-methylvinoxy (*CH2COCH3, 1b), and 2-methylvinoxy (CH3*CHCHO, 1c) radicals. CBS-QB3 predictions for peroxy radical formation agree with experimental data, while the G2 method systematically overestimates peroxy radical stability. RRKM/master equation simulations based on CBS-QB3 data are used to estimate the competition between prompt isomerization and thermalization for the peroxy radicals derived from 1a, 1b, and 1c. The lowest energy isomerization pathway for radicals 4a and 4c (derived from 1a and 1c, respectively) is a 1,4-shift of the acyl hydrogen requiring 19-20 kcal/mol. The resulting hydroperoxyacyl radical decomposes quantitatively to form *OH. The lowest energy isomerization pathway for radical 4b (derived from 1b) is a 1,5-shift of a methyl hydrogen requiring 26 kcal/mol. About 25% of 4a, but only approximately 5% of 4c, isomerizes promptly at 1 atm pressure. Isomerization of 4b is negligible at all pressures studied.
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Affiliation(s)
- Keith T Kuwata
- Department of Chemistry, Macalester College, Saint Paul, Minnesota 55105-1899, USA.
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149
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Abstract
Atmospheric free radicals are low concentration, relatively fast reacting species whose influence is felt throughout the atmosphere. Reactive radicals have a key role in maintaining a balanced atmospheric composition through their central function in controlling the oxidative capacity of the atmosphere. In this tutorial review, the chemistry of three main groups of atmospheric radicals HO(x), NO(x) and XO(x)(X = Cl, Br, I) are examined in terms of their sources, interconversions and sinks. Key examples of the chemistry are given for each group of radicals in their atmospheric context.
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Affiliation(s)
- Paul S Monks
- Department of Chemistry, University of Leicester, UK.
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Bloss WJ, Evans MJ, Lee JD, Sommariva R, Heard DE, Pilling MJ. The oxidative capacity of the troposphere: Coupling of field measurements of OH and a global chemistry transport model. Faraday Discuss 2005; 130:425-36; discussion 491-517, 519-24. [PMID: 16161796 DOI: 10.1039/b419090d] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combination of in situ, ground-based observations of marine boundary layer OH concentrations performed by laser-induced fluorescence at Mace Head, Ireland and Cape Grim, Tasmania, and a global chemistry-transport model (GEOS-CHEM) are used to obtain an estimate of the mean concentration of OH in the global troposphere. The model OH field is constrained to the geographically sparse, observed OH concentration averaged over the duration of the measurement campaigns to remove diurnal and synoptic variability. The mean northern and southern hemispheric OH concentrations obtained are 0.91 x 10(6) cm(-3) and 1.03 x 10(6) cm(-3) respectively, consistent with values determined from methyl chloroform observations. The observational OH dataset is heavily biased towards mid-latitude summer and autumn observations in the northern hemisphere, while the global oxidising capacity is dominated by the tropics which is observed extremely sparsely; the implications of these geographical distributions are discussed.
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Affiliation(s)
- William J Bloss
- School of Chemistry, University of Leeds, Leeds, UK, LS2 9JT.
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