Atmospheric Chemistry of E- and Z-CF3CH═CHF (HFO-1234ze): OH Reaction Kinetics as a Function of Temperature and UV and IR Absorption Cross Sections

2017 ◽  
Vol 121 (43) ◽  
pp. 8322-8331 ◽  
Author(s):  
María Antiñolo ◽  
Iván Bravo ◽  
Elena Jiménez ◽  
Bernabé Ballesteros ◽  
José Albaladejo
Keyword(s):  
Reaction Kinetics ◽  
Cross Sections ◽  
Atmospheric Chemistry ◽  
Ir Absorption ◽  
Absorption Cross

scholarly journals Determination of the absorption cross-sections of higher order iodine oxides at 355 nm and 532 nm

2020 ◽  
Author(s):  
Thomas R. Lewis ◽  
Juan Carlos Gómez Martin ◽  
Mark A. Blitz ◽  
Carlos A. Cuevas ◽  
John M. C. Plane ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Atmospheric Chemistry ◽  
Absorption Cross Section ◽  
Absorption Cross ◽  
Time Resolved ◽  
Flight Mass Spectrometry ◽  
Iodine Oxides ◽  
Photo Ionization

Abstract. Iodine oxides (IxOy) play an important role in the atmospheric chemistry of iodine. They are initiators of new particle formation events in the coastal and polar boundary layer and act as iodine reservoirs in tropospheric ozone-depleting chemical cycles. Despite the importance of the aforementioned processes, the photochemistry of these molecules has not been studied in detail previously. Here, we report the first determination of the absorption cross sections of IxOy, x = 2, 3, 5, y = 1–12 at λ = 355 nm by combining pulsed laser photolysis of I2/O3 gas mixtures in air with time-resolved photo-ionization time-of-flight mass spectrometry, using NO2 actinometry for signal calibration. The oxides selected for absorption cross section determinations are those presenting the strongest signals in the mass spectra, where signals containing 4 iodine atoms are absent. The method is validated by measuring the absorption cross section of IO at 355 nm, σ355 nm, IO = (1.2 ± 0.1) ×  10–18 cm2, which is found to be in good agreement with the most recent literature. The results obtained are: σ355 nm, I2O3 

Atmospheric Chemistry of CHF2CHO:  Study of the IR and UV−Vis Absorption Cross Sections, Photolysis, and OH-, Cl-, and NO3-Initiated Oxidation

2005 ◽  
Vol 109 (16) ◽  
pp. 3652-3662 ◽  
Author(s):  
Stig R. Sellevåg ◽  
Yngve Stenstrøm ◽  
Trygve Helgaker ◽  
Claus J. Nielsen
Keyword(s):  
Cross Sections ◽  
Atmospheric Chemistry ◽  
Absorption Cross

scholarly journals Determination of the absorption cross sections of higher-order iodine oxides at 355 and 532 nm

2020 ◽  
Vol 20 (18) ◽  
pp. 10865-10887
Author(s):  
Thomas R. Lewis ◽  
Juan Carlos Gómez Martín ◽  
Mark A. Blitz ◽  
Carlos A. Cuevas ◽  
John M. C. Plane ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Atmospheric Chemistry ◽  
Absorption Cross Section ◽  
Particle Formation ◽  
Absorption Cross ◽  
Iodic Acid ◽  
Iodine Oxides ◽  
532 Nm

Abstract. Iodine oxides (IxOy) play an important role in the atmospheric chemistry of iodine. They are initiators of new particle formation events in the coastal and polar boundary layers and act as iodine reservoirs in tropospheric ozone-depleting chemical cycles. Despite the importance of the aforementioned processes, the photochemistry of these molecules has not been studied in detail previously. Here, we report the first determination of the absorption cross sections of IxOy, x=2, 3, 5, y=1–12 at λ=355 nm by combining pulsed laser photolysis of I2∕O3 gas mixtures in air with time-resolved photo-ionization time-of-flight mass spectrometry, using NO2 actinometry for signal calibration. The oxides selected for absorption cross-section determinations are those presenting the strongest signals in the mass spectra, where signals containing four iodine atoms are absent. The method is validated by measuring the absorption cross section of IO at 355 nm, σ355nm,IO= (1.2±0.1) ×10-18 cm2, which is found to be in good agreement with the most recent literature. The results obtained are σ355nm,I2O3<5×10-19 cm2 molec.−1, σ355nm,I2O4= (3.9±1.2)×10-18 cm2 molec.−1, σ355nm,I3O6= (6.1±1.6)×10-18 cm2 molec.−1, σ355nm,I3O7= (5.3±1.4)×10-18 cm2 molec.−1, and σ355nm,I5O12= (9.8±1.0)×10-18 cm2 molec.−1. Photodepletion at λ=532 nm was only observed for OIO, which enabled determination of upper limits for the absorption cross sections of IxOy at 532 nm using OIO as an actinometer. These measurements are supplemented with ab initio calculations of electronic spectra in order to estimate atmospheric photolysis rates J(IxOy). Our results confirm a high J(IxOy) scenario where IxOy is efficiently removed during daytime, implying enhanced iodine-driven ozone depletion and hindering iodine particle formation. Possible I2O3 and I2O4 photolysis products are discussed, including IO3, which may be a precursor to iodic acid (HIO3) in the presence of HO2.

Atmospheric Chemistry of 1-Methoxy 2-Propyl Acetate: UV Absorption Cross Sections, Rate Coefficients, and Products of Its Reactions with OH Radicals and Cl Atoms

2016 ◽  
Vol 120 (45) ◽  
pp. 9049-9062 ◽  
Author(s):  
Antonia G. Zogka ◽  
Abdelwahid Mellouki ◽  
Manolis N. Romanias ◽  
Yuri Bedjanian ◽  
Mahmoud Idir ◽  
...  
Keyword(s):  
Cross Sections ◽  
Atmospheric Chemistry ◽  
Uv Absorption ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Absorption Cross ◽  
Propyl Acetate ◽  
Cl Atoms

Absorption Cross Sections and Self-Reaction Kinetics of the IO Radical

1997 ◽  
Vol 101 (5) ◽  
pp. 853-863 ◽  
Author(s):  
Matthew H. Harwood ◽  
James B. Burkholder ◽  
Martin Hunter ◽  
R. W. Fox ◽  
A. R. Ravishankara
Keyword(s):  
Reaction Kinetics ◽  
Cross Sections ◽  
Absorption Cross ◽  
Kinetics Of

Laboratory Studies of CHF2CF2CH2OH and CF3CF2CH2OH: UV and IR Absorption Cross Sections and OH Rate Coefficients between 263 and 358 K

2012 ◽  
Vol 116 (24) ◽  
pp. 6041-6050 ◽  
Author(s):  
María Antiñolo ◽  
Sergio González ◽  
Bernabé Ballesteros ◽  
José Albaladejo ◽  
Elena Jiménez
Keyword(s):  
Cross Sections ◽  
Rate Coefficients ◽  
Ir Absorption ◽  
Absorption Cross ◽  
Laboratory Studies

scholarly journals First remote sensing measurements of ClOOCl along with ClO and ClONO<sub>2</sub> in activated and deactivated Arctic vortex conditions using new ClOOCl IR absorption cross sections

2010 ◽  
Vol 10 (3) ◽  
pp. 931-945 ◽  
Author(s):  
G. Wetzel ◽  
H. Oelhaf ◽  
O. Kirner ◽  
R. Ruhnke ◽  
F. Friedl-Vallon ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Cross Sections ◽  
Stratospheric Ozone ◽  
Equilibrium Constants ◽  
Active Chlorine ◽  
Late Winter ◽  
Ir Absorption ◽  
Absorption Cross ◽  
Mixing Ratios ◽  
Reservoir Species

Abstract. Active chlorine species play a dominant role in the catalytic destruction of stratospheric ozone in the polar vortices during the late winter and early spring seasons. Recently, the correct understanding of the ClO dimer cycle was challenged by the release of new laboratory absorption cross sections (Pope et al., 2007) yielding significant model underestimates of observed ClO and ozone loss (von Hobe et al., 2007). Under this aspect, nocturnal Arctic stratospheric limb emission measurements carried out by the balloon version of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS-B) from Kiruna (Sweden) on 11 January 2001 and 20/21 March 2003 have been reanalyzed with regard to the chlorine reservoir species ClONO2 and the active species, ClO and ClOOCl (Cl2O2). New laboratory measurements of IR absorption cross sections of ClOOCl for various temperatures and pressures allowed for the first time the retrieval of ClOOCl mixing ratios from remote sensing measurements. High values of active chlorine (ClOx) of roughly 2.3 ppbv at 20 km were observed by MIPAS-B in the cold mid-winter Arctic vortex on 11 January 2001. While nighttime ClOOCl shows enhanced values of nearly 1.1 ppbv at 20 km, ClONO2 mixing ratios are less than 0.1 ppbv at this altitude. In contrast, high ClONO2 mixing ratios of nearly 2.4 ppbv at 20 km have been observed in the late winter Arctic vortex on 20 March 2003. No significant ClOx amounts are detectable on this date since most of the active chlorine has already recovered to its main reservoir species ClONO2. The observed values of ClOx and ClONO2 are in line with the established polar chlorine chemistry. The thermal equilibrium constants between the dimer formation and its dissociation, as derived from the balloon measurements, are on the lower side of reported data and in good agreement with values recommended by von Hobe et al. (2007). Calculations with the ECHAM/MESSy Atmospheric Chemistry model (EMAC) using established kinetics show similar chlorine activation and deactivation, compared to the measurements in January 2001 and March 2003, respectively.

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