Temperature-dependent rate coefficients for the reactions of the hydroxyl radical with the atmospheric biogenics isoprene, alpha-pinene and delta-3-carene

Dillon, Terry J.; Dulitz, Katrin; Groß, C. B. M.; Crowley, John N.

doi:10.5194/acp-17-15137-2017

Cited by 12 publications

(12 citation statements)

References 45 publications

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“…Given the good agreement in the temperature dependence of k1 with other measurements, the simplest explanation is some systematic error in determining isoprene concentrations in the reaction cell. That explanation is supported by the recent studies of Dillon et al 22 who determined UV absorption cross sections for isoprene which are approximately 10% greater than those of Campuzano-Jost et al and in good agreement with another determination by Martins et al 111 Dillon et al re-evaluated the Campuzano-Jost data using their new cross sections, generally bringing the Campuzano-Jost et al data in closer agreement to the IUPAC evaluation.…”

Section: Master Equation Modelling and Comparison With Literaturementioning

confidence: 57%

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Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

et al. 2018

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The reaction of the OH radical with isoprene, CH (R1), has been studied over the temperature range 298-794 K and bath gas pressures of nitrogen from 50 to 1670 Torr using laser flash photolysis (LFP) to generate OH and laser-induced fluorescence (LIF) to observe OH removal. Measurements have been made using both a conventional LFP/LIF apparatus and a new high pressure system. The measured rate coefficient at 298 K ( k = (9.90 ± 0.09) × 10 cm molecule s) in the high pressure apparatus is in excellent agreement with the literature, confirming the accuracy of measurements made with this instrument. Above 700 K, the OH decays were no longer single exponentials due to regeneration of OH from adduct decomposition and the establishment of the OH + CH ⇌ HOCH equilibrium (R1a, R-1a). This equilibrium was analyzed by comparison to a master equation model of reaction R1 and determined the well depth for OH addition to carbon C and C to be equal to 153.5 ± 6.2 and 143.4 ± 6.2 kJ mol, respectively. These well depths are in excellent agreement with the present ab initio-CCSD(T)/CBS//M062X/6-311++G(3df,2p)-calculations (154.1 kJ mol for the C adduct). Addition to the less stable C and C adducts is not important. The data above 700 K also indicated that a minor but significant direct abstraction channel, R1b, was also operating with k = (1.3 ± 0.3) × 10 exp(-3.61 kJ mol/ RT) cm molecule s. Additional support for the presence of this abstraction channel comes from our ab initio calculations and from room-temperature proton transfer mass spectrometry product analysis. The literature data on reaction R1 together with the present data were assessed using master equation analysis, using the MESMER package. This analysis produced a refined data set that generates our recommended k( T, [ M]). An analytical representation of k( T, [ M]) and k( T, [ M]) is provided via a Troe expression. The reported experimental data (the sum of addition and abstraction), k = (9.5 ± 0.2) × 10( T/298 K) + (1.3 ± 0.3) × 10 exp(-3.61 kJ mol/ RT) cm molecule s, significantly extend the measured temperature range of R1.

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Section: Master Equation Modelling and Comparison With Literaturementioning

confidence: 57%

“…Reaction R1 appears to be at its high pressure limit above 50 -100 Torr at room temperature, however, there is some controversy as to the onset of the pressure independent region. [19][20][21][22] There is no evidence of any significant role for the abstraction reaction at room temperature.…”

Section: C5h7 + H2o (R1b)mentioning

confidence: 98%

Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

et al. 2018

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“…theoretically derived literature values. Dillon et al (2017) determined a temperature-dependent rate coefficient, for comparability with data in this work, only the rate coefficient determined at 304 K is used. Dillon et al (2017) determined a reaction rate constant of (8.1 ± 0.1) × 10 −11 cm 3 s −1 using an absolute rate approach and Atkinson et al (1986) reported a value of (8.7 ± 0.4) × 10 −11 cm 3 s −1 at 294 K using a relative rate determination approach.…”

Section: Rate Constant Of the Oh + ∆ 3 -Carene Reactionmentioning

confidence: 99%

Atmospheric photooxidation and ozonolysis of Δ<sup>3</sup>-carene and 3-caronaldehyde: Rate constants and product yields

Hantschke¹,

Novelli²,

Bohn³

et al. 2021

Preprint

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Abstract. The oxidation of Δ3-carene and one of its main oxidation products, caronaldehyde, by the OH radical and O3 was investigated in the atmospheric simulation chamber SAPHIR under atmospheric conditions for NOx mixing ratios below 2 ppbv. Within this study, the rate constants of the reaction of Δ3-carene with OH and O3, and of the reaction of caronaldehyde with OH were determined to be (8.0 ± 0.5) × 10−11 cm3 s−1 at 304 K, (4.4 ± 0.2) × 10−17 cm3 s−1 at 300 K and (4.6 ± 1.6) × 10−11 cm3 s−1 at 300 K, respectively, in agreement with previously published values. The yields of caronaldehyde from the reaction of OH and ozone with Δ3-carene were determined to be (0.30 ± 0.05) and (0.06 ± 0.02), respectively. Both values are in reasonably well agreement with reported literature values. An organic nitrate (RONO2) yield from the reaction of NO with RO2 derived from Δ3-carene of (0.25 ± 0.04) was determined from the analysis of the reactive nitrogen species (NOy) in the SAPHIR chamber. The RONO2 yield of the reaction of NO with RO2 derived from the reaction of caronaldehyde with OH was found to be (0.10 ± 0.02). The organic nitrate yields of Δ3-carene and caronaldehyde oxidation with OH are reported here for the first time in the gas phase. An OH yield of (0.65 ± 0.10) was determined from the ozonolysis of Δ3-carene. Calculations of production and destruction rates of the sum of hydroxyl and peroxy radicals (ROx = OH+HO2+RO2) demonstrated that there were no unaccounted production or loss processes of radicals in the oxidation of Δ3-carene for conditions of the the chamber experiments. In an OH free experiment with added OH scavenger, the photolysis frequency of caronaldehyde was obtained from its photolytical decay. The experimental photolysis frequency was a factor of 7 higher than the value calculated from the measured solar acintic flux density, an absorption cross section from the literature and an assumed effective quantum yield of unity for photodissociation.

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“…The isoprene UV-Vis cross section is shown in (Figure 7). The data has been taken from (Dillon et al 2017) and is used for calculating the UV photolysis rate (see Section 3.3). The isoprene UV-Vis absorption peaks at 218 nm with σpeak = 7.93 ± 0.02 × 10 -17 cm -2 molecule -1 and covers a wavelength range of 118 nm to 278 nm.…”

Section: Uv-vis Cross Sectionmentioning

confidence: 99%

“…Figure 7. Isoprene UV-Vis absorption cross section taken from(Dillon et al 2017). The axes shows absorption cross section [cm 2 molecule -1 ] vs. wavelength[μm].…”

mentioning

confidence: 99%

Assessment of Isoprene as a Possible Biosignature Gas in Exoplanets with Anoxic Atmospheres

Zhan¹,

Seager²,

Petkowski³

et al. 2019

Preprint

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Research for possible biosignature gases on habitable exoplanet atmosphere is accelerating, although actual observations are years away. This work adds isoprene, C5H8, to the roster of biosignature gases. We found that formation of isoprene geochemical formation is highly thermodynamically disfavored and has no known abiotic false positives. The isoprene production rate on Earth rivals that of methane (~500 Tg yr -1 ). Unlike methane, on Earth isoprene is rapidly destroyed by oxygen-containing radicals. Although isoprene is predominantly produced by deciduous trees, isoprene production is ubiquitous to a diverse array of evolutionary distant organisms, from bacteria to plants and animals-few, if any at all, volatile secondary metabolite has a larger evolutionary reach. While non-photochemical sinks of isoprene may exist, such as degradation of isoprene by life or other high deposition rates, destruction of isoprene in an anoxic atmosphere is mainly driven by photochemistry. Motivated by the concept that isoprene might accumulate in anoxic environments, we model the photochemistry and spectroscopic detection of isoprene in habitable temperature, rocky exoplanet anoxic atmospheres with a variety of atmosphere compositions under different host star UV fluxes.Limited by an assumed 10 ppm instrument noise floor, habitable atmosphere characterization using JWST is only achievable with transit signal similar or larger than that for a super-Earth sized exoplanet transiting an M dwarf star with a H2-dominated atmosphere. Unfortunately isoprene cannot accumulate to detectable abundance without entering a run-away phase, which occurs at a very high production rate, ~100 times Earth's production rate. In this runaway scenario isoprene will accumulate to > 100 ppm and its spectral features are detectable with ~20 JWST transits. One caveat is that some spectral features are be hard to be distinguish from that of methane. Despite these challenges, isoprene is worth adding to the menu of potential biosignature gases.

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Temperature-dependent rate coefficients for the reactions of the hydroxyl radical with the atmospheric biogenics isoprene, alpha-pinene and delta-3-carene

Cited by 12 publications

References 45 publications

Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

Atmospheric photooxidation and ozonolysis of Δ<sup>3</sup>-carene and 3-caronaldehyde: Rate constants and product yields

Assessment of Isoprene as a Possible Biosignature Gas in Exoplanets with Anoxic Atmospheres

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Temperature-dependent rate coefficients for the reactions of the hydroxyl radical with the atmospheric biogenics isoprene, alpha-pinene and delta-3-carene

Cited by 12 publications

References 45 publications

Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

Kinetics of the Reaction of OH with Isoprene over a Wide Range of Temperature and Pressure Including Direct Observation of Equilibrium with the OH Adducts

Atmospheric photooxidation and ozonolysis of Δ&lt;sup&gt;3&lt;/sup&gt;-carene and 3-caronaldehyde: Rate constants and product yields

Assessment of Isoprene as a Possible Biosignature Gas in Exoplanets with Anoxic Atmospheres

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Atmospheric photooxidation and ozonolysis of Δ<sup>3</sup>-carene and 3-caronaldehyde: Rate constants and product yields