Temperature-dependent absorption cross-sections of gaseous nitric acid and methyl nitrate

Rattigan, Oliver V.; Lutman, E. R.; Jones, R. L.; Cox, R. A.; Clemitshaw, Kevin C.; Williams, Jonathan

doi:10.1016/1010-6030(92)85269-z

Cited by 14 publications

(11 citation statements)

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“…Finally, we estimated the lifetimes of the two alkyl nitrates, using photolysis rates calculated using data from Clemitshaw et al9 and Rattigan et al 33 We conclude that, for both methyl nitrate and ethyl nitrate, loss by photolysis is by far the most important process. Only in the lowest few kilometres of the atmosphere will loss via reaction with OH be signiÐcant.…”

Section: Methyl and Ethyl Nitrate In The Atmospherementioning

confidence: 88%

Rate constants for the reaction between OH and CH3ONO2 and C2H5ONO2 over a range of pressure and temperature

Shallcross¹,

Biggs²,

Canosa‐Mas³

et al. 1997

Faraday Trans.

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Section: Methyl and Ethyl Nitrate In The Atmospherementioning

confidence: 88%

Rate constants for the reaction between OH and CH3ONO2 and C2H5ONO2 over a range of pressure and temperature

Shallcross¹,

Biggs²,

Canosa‐Mas³

et al. 1997

Faraday Trans.

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“…UHP grade nitrogen and oxygen carrier gases were obtained from Airgas and were used as received. Purified nitric acid was made by distilling in vacuum 45 of a liquid mixture of sulfuric acid (98%; Mallinckrodt Baker) and nitric acid (70%; Mallinckrodt NO, and H 2 O at 1:1:2 mole ratios. We monitored the time dependence of NO 2 absorption at 564.00 nm both immediately after the mixing and up to 60 h after the mixing; we found that the NO 2 absorption reached a minimum after we let the mixture to react and equilibrate for about 24 h. From changes in NO 2 concentration upon mixing and after 24 h of reaction, we derived an equilibrium HONO concentration.…”

Section: Experimental Methodsmentioning

confidence: 99%

Role of Methyl-2-nitrophenol Photolysis as a Potential Source of OH Radicals in the Polluted Atmosphere: Implications from Laboratory Investigation

Sangwan

Zhu

2018

J. Phys. Chem. A

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Methyl-substituted 2-nitrophenols are important components of "brown carbon" from biomass burning. Photolysis is their major gas-phase degradation pathway. To determine the extent of light absorptions by 4-methyl-2-nitrophenol and 5-methyl-2-nitrophenol, we obtained their absorption cross sections in the 295-400 nm region by using cavity ring-down spectroscopy. Cross-section values for 4-methyl-2-nitrophenol were (1.01 ± 0.07) × 10, (5.72 ± 0.39) × 10, and (1.80 ± 0.17) × 10 cm/molecule at 295, 345, and 400 nm, where errors quoted represent 1σ measurement uncertainty. Cross-section values for 5-methyl-2-nitrophenol were (9.04 ± 0.77) × 10, (5.89 ± 0.54) × 10, and (2.81 ± 0.14) × 10 cm/molecule at 295, 345, and 400 nm. The HONO, NO, and OH formation channels following 308 and 351 nm photolysis of methyl-2-nitrophenols were investigated. The OH quantum yields at 308 and 351 nm were obtained as the ratio of the OH concentration generated in pump/probe laser overlap region to the photon density absorbed by methyl-substituted 2-nitrophenol in the same region; they were 0.066 ± 0.021 and 0.031 ± 0.017 for 4-methyl-2-nitrophenol and 0.078 ± 0.038 and 0.042 ± 0.015 for 5-methyl-2-nitrophenol, where uncertainties represent 1σ precision. The average HONO quantum yields at 308 and 351 nm were 0.26 ± 0.06 and 0.26 ± 0.03 for 4-methyl-2-nitrophenol and 0.37 ± 0.05 and 0.35 ± 0.06 for 5-methyl-2-nitrophenol. Estimated OH production rates from photolyzing 10 pptv of 4-methyl- and 5-methyl-2-nitrophenol are 2.3 × 10 and 3.0 × 10 molecules·cm·s at 16.9° zenith angle.

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“…The subsequent rise in the OH signal results from the reactions of the photolysis products to form OH. As shown above, H atoms are formed with a small yield in the 248 nm photolysis and can react with to CH 3 ONO 2 generate either OH or via reaction (6). The H 2 CH 2 ONO 2 radical, channel (6b), is expected to decompose thermally into and not to a †ect the OH signal.…”

Section: Oxygen and Hydrogen Atom Resonance ñUorescencementioning

confidence: 94%

“…In the 248 nm photolysis of methyl nitrate, H atoms were detected via atomic resonance Ñuorescence. We assign an (6) was obtained by analysing the H atom temporal proÐles in the presence of varying concentration of to be (3 ^1) ] 10~13 cm3 molecule~1 s~1. CH 3 ONO 2 This value is similar to that obtained from the analysis of OH temporal proÐles (see below).1 The reason for the large error bar in the rate constant is the small quantum yield of H atom and, the consequently, small H atom signal levels.…”

Section: Oxygen and Hydrogen Atom Resonance ñUorescencementioning

confidence: 99%

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Atmospheric fate of several alkyl nitrates Part 2UV absorption cross-sections and photodissociation quantum yields

Talukdar¹,

Burkholder²,

Hunter³

et al. 1997

Faraday Trans.

110

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The UV absorption cross-sections of methyl, ethyl and isopropyl nitrate between 233 and 340 nm have been measured using a diode array spectrometer in the temperature range 240È360 K. The absorption cross-sections of these alkyl nitrates decrease with increasing wavelength and decrease with decreasing temperature for j [ 280 nm. The photodissociation quantum yield for to produce and was found to be essentially unity at 248 nm using transient UV absorption methods. CHand H atoms in the photodissociation of methyl nitrate at 248 and 308 nm were found to be negligible using resonance Ñuorescence detection of the atoms. High quantum yields for O atoms were measured following 193 nm photolysis of methyl nitrate. The OH radical was measured to be a photoproduct with a very small quantum yield. Using the OH rate coefficients reported in the accompanying paper and the UV absorption cross-sections and the photodissociation quantum yields measured here, the Ðrst-order rate constants for atmospheric loss of methyl, ethyl and isopropyl nitrate were calculated. Photolysis was found to be the dominant atmospheric loss process for the three alkyl nitrates.

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Temperature-dependent absorption cross-sections of gaseous nitric acid and methyl nitrate

Cited by 14 publications

References 0 publications

Rate constants for the reaction between OH and CH3ONO2 and C2H5ONO2 over a range of pressure and temperature

Rate constants for the reaction between OH and CH3ONO2 and C2H5ONO2 over a range of pressure and temperature

Role of Methyl-2-nitrophenol Photolysis as a Potential Source of OH Radicals in the Polluted Atmosphere: Implications from Laboratory Investigation

Atmospheric fate of several alkyl nitrates Part 2UV absorption cross-sections and photodissociation quantum yields

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