LIF studies of iodine oxide chemistry : Part 3. Reactions IO + NO3 → OIO + NO2, I + NO3 → IO + NO2, and CH2I + O2 → (products): implications for the chemistry of the marine atmosphere at night

Dillon, Terry J.; Tucceri, María E.; Sander, R.; Crowley, John N.

doi:10.1039/b717386e

Cited by 35 publications

(45 citation statements)

References 49 publications

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“…Based on our signal-to-noise ratio, we further constrain the primary IO yield to be less than 1%, resolving some debate among published results. [23][24][25][26] The formation of IO is likely due to (R8). 5,14 CH 2 OO + I -H 2 CO + IO (R8)…”

Section: O( 1 D) + H 2 O -2oh (R5)mentioning

confidence: 99%

The UV absorption spectrum of the simplest Criegee intermediate CH₂OO

Ting

Chen

Chao

et al. 2014

Phys. Chem. Chem. Phys.

129

224

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SO 2 scavenging and self-reaction of CH 2 OO were utilized for the decay of CH 2 OO to extract the absorption spectrum of CH 2 OO under bulk conditions. Absolute absorption cross sections of CH 2 OO at 308.4 and 351.8 nm were obtained from laser-depletion measurements in a jet-cooled molecular beam. The peak cross section is (1.23 AE 0.18) Â 10 À17 cm 2 at 340 nm.Ozonolysis is a major removal mechanism in the troposphere for unsaturated hydrocarbons which are emitted in large quantities from both natural and human sources. Now it is generally accepted that ozonolysis of alkenes proceeds via Criegee intermediates, highly reactive species postulated in 1949 by Rudolf Criegee. 1,2 In the troposphere, Criegee intermediates are involved in several important atmospheric reactions, 3 including reactions with SO 2 and NO 2 , 4-7 or can be photolyzed by near UV light, 7-10 as shown for CH 2 OO in (R1)-(R4).The formation of SO 3 and NO 3 , as in (R2) and (R3), plays an important role in atmospheric chemistry, 11,12 including aerosol and cloud formation. The formation of O( 1 D), as in (R4), will result in OH formation through (R5).Because CH 2 OO absorbs strongly at wavelengths longer than 300 nm, 7-9 tropospheric photolysis of CH 2 OO would be quite efficient with an effective photolysis lifetime on the order of 1 second. 8 As a result, the OH formation of (R4) + (R5) may contribute significantly to the atmospheric OH concentrations.Despite their importance, the direct detection of Criegee intermediates was not realized until recently. 4,13 Welz et al. 4 reported an efficient way to prepare Criegee intermediates. For example, CH 2 OO can be prepared via (R6) + (R7a). Welz et al. 4 also demonstrated the direct detection of CH 2 OO by using vacuum UV photoionization mass spectrometry. The parent ion CH 2 O 2 + was observed when the photon energy exceeded the ionization energy of CH 2 OO (10.0 eV); other isomers like dioxirane and formic acid were excluded due to their different ionization energies. 4 At low pressure, the yield of (R7a) is close to unity, 14,15 while the adduct formation (R7b) may dominate at near atmospheric pressures. 14The kinetics of CH 2 OO reactions with SO 2 and NO 2 were investigated by Welz et al. 4 and by Stone et al. 5 by observing the disappearance of CH 2 OO and by detecting the H 2 CO products, respectively. The rate coefficients of these reactions were found to be unexpectedly rapid and imply a substantially greater role of Criegee intermediates in models of tropospheric sulfate and nitrate chemistry.Beames et al. 8 recorded the UV spectrum of CH 2 OO through observing its depletion in a molecular beam upon laser irradiation (an action spectrum). Based on their laser pulse energy and spot size, Beames et al. 8 roughly estimated the peak absorption cross section to be 5 Â 10 À17 cm 2 (at 335 nm with FWHM B40 nm). Lehman et al. 10 measured the angular and velocity distributions of the O( 1 D) photoproduct arising from UV excitation of CH 2 OO in the 300-365 nm range. From the observed

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Section: O( 1 D) + H 2 O -2oh (R5)mentioning

confidence: 99%

The UV absorption spectrum of the simplest Criegee intermediate CH₂OO

Ting

Chen

Chao

et al. 2014

Phys. Chem. Chem. Phys.

129

224

View full text Add to dashboard Cite

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“…Corrections (20%) were made for the excimer beam divergence, and attenuation by the exit window. The joulemeter itself had been calibrated in previous work (Dillon et al, 2006b;Dillon et al, 2008). The errors in calculating [Cl] 0 by this method were estimated as 10% (precision) with an additional 30% (systematic error/accuracy) associated with imperfections in the photolysis beam profile, and overlap with the probe laser.…”

Section: Reagent Handling and Concentration Measurementsmentioning

confidence: 99%

Direct detection of OH formation in the reactions of HO2 with CH3C(O)O2 and other substituted peroxy radicals

2008

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Abstract. This work details the first direct observation of OH as a product from (R1): HO 2 +CH 3 C(O)O 2 →(products), which has generally been considered an atmospheric radical termination process. The technique of pulsed laser photolysis radical generation, coupled to calibrated laser induced fluorescence detection was used to measure an OH product yield for (R1) of α 1 (298 K)=(0.5±0.2). This study of (R1) included the measurement of a rate coefficient k 1 (298 K)=(1.4±0.5)×10 −11 cm 3 molecule −1 s −1 , substantially reducing the uncertainties in modelling this important atmospheric reaction. OH was also detected as a product from the reactions of HO 2 with three other carbonylcontaining peroxy radicals, albeit at smaller yield, e.g. (R2): HO 2 +CH 3 C(O)CH 2 O 2 →(products), α 2 ≈0.15. By contrast, OH was not observed (α<0.06) as a major product from reactions where carbonyl functionality was absent, e.g. HO 2 +HOCH 2 CH 2 O 2 (R8), and HO 2 +CH 3 CH(OH)CH 2 O 2 (R9).

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“…The resulting atomic iodine will then react rapidly with O 3 to form IO (Reaction R2). The IO produced can react with NO 3 (Reaction R3) with a rate coefficient of 9×10 −12 cm 3 molecule −1 s −1 (Dillon et al, 2008), which will lead to additional NO 3 consumption and will compete with IO+IO for nighttime OIO formation.…”

Section: Implications For O 3 Io Oio and No Xmentioning

confidence: 99%

In situ measurements of molecular iodine in the marine boundary layer: the link to macroalgae and the implications for O3, IO, OIO and NOx

et al. 2010

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Abstract. Discrete in situ atmospheric measurements of molecular iodine (I 2 ) were carried out at Mace Head and Mweenish Bay on the west coast of Ireland using diffusion denuders in combination with a gas chromatography-mass spectrometry (GC-MS) method. I 2 , IO and OIO were also measured by long-path differential optical absorption spectroscopy (LP-DOAS). The simultaneous denuder and LP-DOAS I 2 measurements were well correlated (R 2 =0.80) but the denuder method recorded much higher concentrations. This can be attributed to the fact that the in situ measurements were made near to macroalgal sources of I 2 in the intertidal zone, whereas the LP-DOAS technique provides distance-averaged mixing ratios of an inhomogeneous distribution along the light-path. The observed mixing ratios of I 2 at Mweenish Bay were significantly higher than that at Mace Head, which is consistent with differences in local algal biomass density and algal species composition. Above algal beds, levels of I 2 were found to correlate inversely with tidal height and positively with the concentrations of O 3 in the surrounding air, indicating a role for O 3 in the production of I 2 from macroalgae, as has been previously suggested from laboratory studies. However, measurements made ∼150 m away from the algal beds showed a negative correlation between O 3 and I 2 during both day and night. We interpret these results to indicate that the released I 2 can also lead to O 3 destruction via the reaction of O 3 with I atoms that are formed by the photolysis of I 2 during the day and via the Correspondence to: T. Hoffmann (hoffmant@uni-mainz.de ) reaction of I 2 with NO 3 radicals at night. The results show that the concentrations of daytime IO are correlated with the mixing ratios of I 2 , and suggest that the local algae sources dominate the inorganic iodine chemistry at Mace Head and Mweenish Bay.

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LIF studies of iodine oxide chemistry : Part 3. Reactions IO + NO3 → OIO + NO2, I + NO3 → IO + NO2, and CH2I + O2 → (products): implications for the chemistry of the marine atmosphere at night

Cited by 35 publications

References 49 publications

The UV absorption spectrum of the simplest Criegee intermediate CH₂OO

The UV absorption spectrum of the simplest Criegee intermediate CH₂OO

Direct detection of OH formation in the reactions of HO<sub>2</sub> with CH<sub>3</sub>C(O)O<sub>2</sub> and other substituted peroxy radicals

In situ measurements of molecular iodine in the marine boundary layer: the link to macroalgae and the implications for O<sub>3</sub>, IO, OIO and NO<sub>x</sub>

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LIF studies of iodine oxide chemistry : Part 3. Reactions IO + NO3 → OIO + NO2, I + NO3 → IO + NO2, and CH2I + O2 → (products): implications for the chemistry of the marine atmosphere at night

Cited by 35 publications

References 49 publications

The UV absorption spectrum of the simplest Criegee intermediate CH2OO

The UV absorption spectrum of the simplest Criegee intermediate CH2OO

Direct detection of OH formation in the reactions of HO&lt;sub&gt;2&lt;/sub&gt; with CH&lt;sub&gt;3&lt;/sub&gt;C(O)O&lt;sub&gt;2&lt;/sub&gt; and other substituted peroxy radicals

In situ measurements of molecular iodine in the marine boundary layer: the link to macroalgae and the implications for O&lt;sub&gt;3&lt;/sub&gt;, IO, OIO and NO&lt;sub&gt;x&lt;/sub&gt;

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The UV absorption spectrum of the simplest Criegee intermediate CH₂OO

The UV absorption spectrum of the simplest Criegee intermediate CH₂OO

Direct detection of OH formation in the reactions of HO<sub>2</sub> with CH<sub>3</sub>C(O)O<sub>2</sub> and other substituted peroxy radicals

In situ measurements of molecular iodine in the marine boundary layer: the link to macroalgae and the implications for O<sub>3</sub>, IO, OIO and NO<sub>x</sub>