Cavity ring-down spectroscopic study of acetaldehyde photolysis in the gas phase, on aluminum surfaces, and on ice films

Tang, Yongxin; Zhu, Lin; Chu, Liang T.; Xiang, Bin

doi:10.1016/j.chemphys.2006.08.005

Cited by 7 publications

(6 citation statements)

References 32 publications

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“…As can be seen, the HCO quantum yields were near constant, at about 0.62 to within experimental error limit, in the 280−305 nm region; they then decreased with increasing wavelength in the 308−315 nm region, due to dissociation at near-threshold wavelengths. The HCO quantum yields from the glycolaldehyde photolysis were smaller than those from the acetaldehyde photolysis, due to the opening up of photolysis pathways other than the HCO formation channel from the glycolaldehyde photolysis.…”

Section: Resultsmentioning

confidence: 90%

Photolysis of Glycolaldehyde in the 280−340 nm Region

Zhu

2010

J. Phys. Chem. A

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We have investigated the gas-phase UV photolysis of glycolaldehyde (HOCH(2)CHO) by laser photolysis combined with cavity ring-down spectroscopy. Absorption cross sections of glycolaldehyde in the 280-340 nm region were measured by cavity ring-down spectroscopy. The HCO + CH(2)OH and the OH + CH(2)CHO product channels following the photolysis of glycolaldehyde were directly examined. The average HCO quantum yields from the glycolaldehyde photolysis were 0.61 +/- 0.08, 0.59 +/- 0.05, 0.61 +/- 0.16, 0.66 +/- 0.09, 0.61 +/- 0.11, 0.65 +/- 0.05, 0.47 +/- 0.04, 0.52 +/- 0.09, and 0.45 +/- 0.05 at 280, 285, 290, 295, 300, 305, 308, 310, and 315 nm, where the error quoted (1sigma) represents experimental scatter. The average OH quantum yield from the photolysis of glycolaldehyde at 308 nm was 0.11 +/- 0.02, where the error quoted (1sigma) represents measurement uncertainty. End products such as CO, H(2)CO, (CHO)(2), CH(3)OH, HCOOH, and CO(2) were detected from the 308 nm photolysis of glycolaldehyde. The yields of CO, H(2)CO, (CHO)(2), CH(3)OH, and HCOOH were estimated. We also directly measured the rate constant for the reaction between the OH radical and glycolaldehyde. The rate constant obtained was (1.01 +/- 0.20) x 10(-11) cm(3) molecule(-1) s(-1), where the error quoted (1sigma) represents measurement uncertainty. Atmospheric implications of the results are discussed.

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Section: Resultsmentioning

confidence: 90%

Photolysis of Glycolaldehyde in the 280−340 nm Region

Zhu

2010

J. Phys. Chem. A

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“…Formaldehyde production observed in nitrogen at high conversion efficiency may result from subsequent reactions of acetaldehyde and acetone formed in the discharge, such as α-cleavage of acetaldehyde, giving HC • O, followed by H abstraction …”

Section: Resultsmentioning

confidence: 99%

Detailed Characterization of 2-Heptanone Conversion by Dielectric Barrier Discharge in N₂ and N₂/O₂ Mixtures

Chiper¹,

Blin-Simiand²,

Héninger³

et al. 2009

J. Phys. Chem. A

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The products of 2-heptanone conversion by dielectric barrier discharge plasma are analyzed under different conditions: alternating current (ac) or pulsed mode of excitation, variable energy, variable composition of the carrier gas. The efficiency of the conversion is higher using a pulse excitation mode than an ac mode. With a small oxygen percentage (about 2-3%) added to nitrogen, 2-heptanone is about 30% more efficiently removed than in pure nitrogen, while the 2-heptanone removal decreases with an oxygen percentage higher than 3%. A new analysis method, based on chemical ionization mass spectrometry, is used for volatile organic compound detection along with chromatography. Several products issued from 2-heptanone conversion with ac excitation are identified in nitrogen and in air, and a chemical scheme is proposed to explain their formation and their treatment by the discharge. It appears that byproducts are issued not only from oxidation reactions, but also from C-C bond cleavage by collisions with electrons or nitrogen excited states.

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“…In this work we produced HCO radicals via two independent methods: the 308 nm photodissociation of acetaldehyde, CH 3 CHO → CH 3 + HCO, and the chemical reaction Cl + H 2 CO → HCl + HCO. In the former, HCO was generated in a 1:1 stoichiometric ratio with CH 3 using 308 nm photolysis (4 or 10 Hz, ∼50 mJ cm –2 pulse –1 ) of acetaldehyde ([CH 3 CHO] 0 ≈ (1–2) × 10 14 cm –3 ) or d 4 -acetaldehyde (for production of DCO + CD 3 ) in excess He at a total pressure of 4 Torr and a temperature of 298 K. Under collisionless conditions acetaldehyde is assumed to yield predominantly CH 3 + HCO (quantum yield: 0.91 ± 0.10) . The net quantum yield for all dissociative processes is significantly reduced with increasing pressure due to collisional deactivation of photoexcited acetaldehyde and is ∼30% near atmospheric pressures at 308 nm. − The Stern–Volmer plots presented in Moortgat et al predict that collisional deactivation is insignificant at 4 Torr.…”

Section: Methodsmentioning

confidence: 99%

Valence Photoionization and Autoionization of the Formyl Radical

et al. 2021

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We have used 308 nm photolysis of acetaldehyde to measure a photoionization spectrum of the formyl (HCO) radical between 8 and 11.5 eV using an 11 meV FWHM photoionization energy resolution. We have confirmed that the formyl radical is the carrier of the spectrum by generating an identical spectrum of the HCO product in the Cl + H 2 CO reaction. The spectrum of HCO and its deuterated isotopologue (DCO) have several resolved autoionizing resonances above the Franck−Condon envelope, which we assign to autoionization after initial excitation into neutral 3sσ and 3p Rydberg states converging to the first triplet excited state of HCO + (a3 A′). The quantum defects for these states are δ 3sσ = 1.06 ± 0.02 and δ 3p = 0.821 ± 0.019. We report absolute photoionization crosssection measurements of σ HCO PI (9.907 eV) = 4.5 ± 0.9 Mb, σ HCO PI (10.007 eV) = 4.8 ± 1.0 Mb, σ HCO PI (10.107 eV) = 6.0 ± 1.2 Mb, σ HCO PI (10.107 eV) = 5.7 ± 1.2 Mb, and σ HCO PI (10.304 eV) = 10.6 ± 2.2 Mb relative to the photoionization cross section of the methyl radical. The absolute cross-section measurements are a factor of ∼1.5 larger than those determined in past studies, although the presence of strong autoionizing features supports a dependence on photoionization energy resolution. We propose that the semiempirical model of Xu and Pratt for estimation of free radical photoionization cross sections is more accurate when applied with a reference species containing the same atoms as the free radical rather than isoelectronic species with different atoms.

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Cavity ring-down spectroscopic study of acetaldehyde photolysis in the gas phase, on aluminum surfaces, and on ice films

Cited by 7 publications

References 32 publications

Photolysis of Glycolaldehyde in the 280−340 nm Region

Photolysis of Glycolaldehyde in the 280−340 nm Region

Detailed Characterization of 2-Heptanone Conversion by Dielectric Barrier Discharge in N₂ and N₂/O₂ Mixtures

Valence Photoionization and Autoionization of the Formyl Radical

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Cavity ring-down spectroscopic study of acetaldehyde photolysis in the gas phase, on aluminum surfaces, and on ice films

Cited by 7 publications

References 32 publications

Photolysis of Glycolaldehyde in the 280−340 nm Region

Photolysis of Glycolaldehyde in the 280−340 nm Region

Detailed Characterization of 2-Heptanone Conversion by Dielectric Barrier Discharge in N2 and N2/O2 Mixtures

Valence Photoionization and Autoionization of the Formyl Radical

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Detailed Characterization of 2-Heptanone Conversion by Dielectric Barrier Discharge in N₂ and N₂/O₂ Mixtures