Heterogeneous–Homogeneous and Homogeneous–Heterogeneous Processes in Atmospheric Chemistry

2019 ◽  
pp. 225-248
Author(s):  
Robert Bakhtchadjian
Keyword(s):  
Atmospheric Chemistry ◽  
Heterogeneous Processes

scholarly journals Evaluated kinetic and photochemical data for atmospheric chemistry: Volume V – heterogeneous reactions on solid substrates

2010 ◽  
Vol 10 (2) ◽  
pp. 5233-5564 ◽  
Author(s):  
J. N. Crowley ◽  
M. Ammann ◽  
R. A. Cox ◽  
R. G. Hynes ◽  
M. E. Jenkin ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Kinetic Data ◽  
Solid Particles ◽  
Heterogeneous Reactions ◽  
Detailed Data ◽  
Adsorption Parameters ◽  
Solid Substrates ◽  
Heterogeneous Processes ◽  
Acid Hydrate ◽  
Sulfuric Acid Hydrate

Abstract. This article, the fifth in the ACP journal series, presents data evaluated by the IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry. It covers the heterogeneous processes on surfaces of solid particles present in the atmosphere, for which uptake coefficients and adsorption parameters have been presented on the IUPAC website in 2009. The article consists of an introduction and guide to the evaluation, giving a unifying framework for parameterisation of atmospheric heterogeneous processes. We provide summary sheets containing the recommended uptake parameters for the evaluated processes. Four substantial appendices contain detailed data sheets for each process considered for ice, mineral dust, sulfuric acid hydrate and nitric acid hydrate surfaces, which provide information upon which the recommendations are made.

scholarly journals Evaluated kinetic and photochemical data for atmospheric chemistry: Volume VI – heterogeneous reactions with liquid substrates

2012 ◽  
Vol 12 (12) ◽  
pp. 32109-32472
Author(s):  
M. Ammann ◽  
R. A. Cox ◽  
J. N. Crowley ◽  
M. E. Jenkin ◽  
A. Mellouki ◽  
...  
Keyword(s):  
Experimental Data ◽  
Sulfuric Acid ◽  
Atmospheric Chemistry ◽  
Kinetic Data ◽  
Chemical Kinetic ◽  
Heterogeneous Reactions ◽  
Aqueous Electrolytes ◽  
Adsorption Parameters ◽  
Heterogeneous Processes ◽  
Halide Salts

Abstract. This article, the sixth in the ACP journal series, presents data evaluated by the IUPAC Task Group on Atmospheric Chemical Kinetic Data Evaluation. It covers the heterogeneous processes involving liquid particles present in the atmosphere, for which uptake coefficients and adsorption parameters have been presented on the IUPAC website since 2009. The article consists of an introduction and guide to the evaluation, giving a unifying framework for parameterisation of atmospheric heterogeneous processes. We provide summary sheets containing the recommended uptake parameters for the evaluated processes. The experimental data on which the recommendations are based are provided in data sheets in separate appendices for the four surfaces considered: liquid water, deliquesced halide salts, other aqueous electrolytes and sulfuric acid.

scholarly journals The role of chlorine in global tropospheric chemistry

2019 ◽  
Vol 19 (6) ◽  
pp. 3981-4003 ◽  
Author(s):  
Xuan Wang ◽  
Daniel J. Jacob ◽  
Sebastian D. Eastham ◽  
Melissa P. Sulprizio ◽  
Lei Zhu ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Chemistry ◽  
Sea Salt ◽  
Tropospheric Chemistry ◽  
Mixing Ratios ◽  
Sea Salt Aerosol ◽  
Oxidation Of Methane ◽  
Heterogeneous Processes ◽  
Marine Air ◽  
Global Mean

Abstract. We present a comprehensive simulation of tropospheric chlorine within the GEOS-Chem global 3-D model of oxidant–aerosol–halogen atmospheric chemistry. The simulation includes explicit accounting of chloride mobilization from sea salt aerosol by acid displacement of HCl and by other heterogeneous processes. Additional small sources of tropospheric chlorine (combustion, organochlorines, transport from stratosphere) are also included. Reactive gas-phase chlorine Cl*, including Cl, ClO, Cl2, BrCl, ICl, HOCl, ClNO3, ClNO2, and minor species, is produced by the HCl+OH reaction and by heterogeneous conversion of sea salt aerosol chloride to BrCl, ClNO2, Cl2, and ICl. The model successfully simulates the observed mixing ratios of HCl in marine air (highest at northern midlatitudes) and the associated HNO3 decrease from acid displacement. It captures the high ClNO2 mixing ratios observed in continental surface air at night and attributes the chlorine to HCl volatilized from sea salt aerosol and transported inland following uptake by fine aerosol. The model successfully simulates the vertical profiles of HCl measured from aircraft, where enhancements in the continental boundary layer can again be largely explained by transport inland of the marine source. It does not reproduce the boundary layer Cl2 mixing ratios measured in the WINTER aircraft campaign (1–5 ppt in the daytime, low at night); the model is too high at night, which could be due to uncertainty in the rate of the ClNO2+Cl- reaction, but we have no explanation for the high observed Cl2 in daytime. The global mean tropospheric concentration of Cl atoms in the model is 620 cm−3 and contributes 1.0 % of the global oxidation of methane, 20 % of ethane, 14 % of propane, and 4 % of methanol. Chlorine chemistry increases global mean tropospheric BrO by 85 %, mainly through the HOBr+Cl- reaction, and decreases global burdens of tropospheric ozone by 7 % and OH by 3 % through the associated bromine radical chemistry. ClNO2 chemistry drives increases in ozone of up to 8 ppb over polluted continents in winter.

scholarly journals Evaluated kinetic and photochemical data for atmospheric chemistry: Volume V – heterogeneous reactions on solid substrates

2010 ◽  
Vol 10 (18) ◽  
pp. 9059-9223 ◽  
Author(s):  
J. N. Crowley ◽  
M. Ammann ◽  
R. A. Cox ◽  
R. G. Hynes ◽  
M. E. Jenkin ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Kinetic Data ◽  
Solid Particles ◽  
Heterogeneous Reactions ◽  
Detailed Data ◽  
Adsorption Parameters ◽  
Solid Substrates ◽  
Heterogeneous Processes ◽  
Acid Hydrate ◽  
Sulfuric Acid Hydrate

Abstract. This article, the fifth in the ACP journal series, presents data evaluated by the IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry. It covers the heterogeneous processes on surfaces of solid particles present in the atmosphere, for which uptake coefficients and adsorption parameters have been presented on the IUPAC website in 2010. The article consists of an introduction and guide to the evaluation, giving a unifying framework for parameterisation of atmospheric heterogeneous processes. We provide summary sheets containing the recommended uptake parameters for the evaluated processes. Four substantial appendices contain detailed data sheets for each process considered for ice, mineral dust, sulfuric acid hydrate and nitric acid hydrate surfaces, which provide information upon which the recommendations are made.

scholarly journals Evaluated kinetic and photochemical data for atmospheric chemistry: Volume VI – heterogeneous reactions with liquid substrates

2013 ◽  
Vol 13 (16) ◽  
pp. 8045-8228 ◽  
Author(s):  
M. Ammann ◽  
R. A. Cox ◽  
J. N. Crowley ◽  
M. E. Jenkin ◽  
A. Mellouki ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Kinetic Data ◽  
Lower Stratosphere ◽  
Marine Boundary Layer ◽  
Chemical Kinetic ◽  
Heterogeneous Reactions ◽  
Adsorption Parameters ◽  
Upper Troposphere ◽  
Heterogeneous Processes ◽  
Halide Salts

Abstract. This article, the sixth in the ACP journal series, presents data evaluated by the IUPAC Task Group on Atmospheric Chemical Kinetic Data Evaluation. It covers the heterogeneous processes involving liquid particles present in the atmosphere with an emphasis on those relevant for the upper troposphere/lower stratosphere and the marine boundary layer, for which uptake coefficients and adsorption parameters have been presented on the IUPAC website since 2009. The article consists of an introduction and guide to the evaluation, giving a unifying framework for parameterisation of atmospheric heterogeneous processes. We provide summary sheets containing the recommended uptake parameters for the evaluated processes. The experimental data on which the recommendations are based are provided in data sheets in separate appendices for the four surfaces considered: liquid water, deliquesced halide salts, other aqueous electrolytes and sulfuric acid.

scholarly journals The role of chlorine in tropospheric chemistry

2018 ◽  
Author(s):  
Xuan Wang ◽  
Daniel J. Jacob ◽  
Sebastian D. Eastham ◽  
Melissa P. Sulprizio ◽  
Lei Zhu ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Chemistry ◽  
Sea Salt ◽  
Tropospheric Chemistry ◽  
Mixing Ratios ◽  
Sea Salt Aerosol ◽  
Oxidation Of Methane ◽  
Heterogeneous Processes ◽  
Marine Air ◽  
Global Mean

Abstract. We present a comprehensive simulation of tropospheric chlorine within the GEOS-Chem global 3-D model of oxidant-aerosol-halogen atmospheric chemistry. The simulation includes explicit accounting of chloride mobilization from sea-salt aerosol by acid displacement of HCl and by other heterogeneous processes. Additional sources of tropospheric chlorine (combustion, organochlorines, transport from stratosphere) are small in comparison. Reactive gas-phase chlorine Cl*, including Cl, ClO, Cl2, BrCl, ICl, HOCl, ClNO3, ClNO2, and minor species, is produced by the HCl + OH reaction and by heterogeneous conversion of sea-salt aerosol chloride to BrCl, ClNO2, Cl2, and ICl. The model simulates successfully the observed mixing ratios of HCl in marine air (highest at northern mid-latitudes) and the associated HNO3 decrease from acid displacement. It captures the high ClNO2 mixing ratios observed in continental surface air at night with chlorine of sea salt origin transported inland as HCl and fine aerosol. It simulates successfully the vertical profiles of HCl measured from aircraft, where enhancements in the continental boundary layer can again be explained by transport inland of the marine source. It does not reproduce the boundary layer Cl2 mixing ratios measured in the WINTER aircraft campaign (1–5 ppt in the daytime, low at night); the model is too high at night compared to WINTER observations, which could be due to uncertainty in the rate of the ClNO2 + Cl− reaction, but we have no explanation for the daytime observations. The global mean tropospheric concentration of Cl atoms in the model is 620 cm−3 and contributes 1.0 % of the global oxidation of methane, 20 % of ethane, 14 % of propane, and 4 % of methanol. Chlorine chemistry increases global mean tropospheric BrO by 85 %, mainly through the HOBr + Cl− reaction, and decreases global burdens of tropospheric ozone by 7 % and OH by 3 % through the associated bromine radical chemistry. ClNO2 chemistry drives increases in ozone of up to 8 ppb over polluted continents in winter.

The Importance of Photodissociative Trichloromethanol for Atmospheric Chemistry

2003 ◽  
Vol 68 (12) ◽  
pp. 2297-2308 ◽  
Author(s):  
Max Mühlhäuser ◽  
Melanie Schnell ◽  
Sigrid D. Peyerimhoff
Keyword(s):  
Energy Range ◽  
Excited States ◽  
Atmospheric Chemistry ◽  
Configuration Interaction ◽  
Configuration Interaction Calculations

Multireference configuration interaction calculations are carried out for ground and excited states of trichloromethanol to investigate two important photofragmentation processes relevant to atmospheric chemistry. For CCl3OH five low-lying excited states in the energy range between 6.1 and 7.1 eV are found to be highly repulsive for C-Cl elongation leading to Cl2COH (X2A') and Cl (X2P). Photodissociation along C-O cleavage resulting in Cl3C (X2A') and OH (X2Π) has to overcome a barrier of about 0.8 eV (13A'', 11A'') and 1.2 eV (13A') because the low-lying excited states 11A'', 13A' and 13A'' become repulsive only after elongating the C-O bond by about 0.3 Å.

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