Absolute Photoionization Cross Section of the Simplest Enol, Vinyl Alcohol

Abstract

The absolute photoionization cross section of vinyl alcohol was determined by multiplexed photoionization mass spectrometry of the Norrish type II photodissociation of butanal at 308 nm. The measured cross sections at 10.005 and 10.205 eV are 7.5 ± 1.9 and 8.1 ± 1.9 MB, respectively. A higher signal-to-noise ratio photoionization spectrum of vinyl alcohol was recorded via the pyrolysis of 2-chloroethanol and scaled to the absolute cross sections measured using the Norrish type II method. From a comparison of our spectrum with previously reported photoelectron spectra we conclude that vinyl alcohol is mainly ionized by direct ionization in the energy range of 9−9.6 eV, whereas autoionization is responsible for the steady rise in the photoionization spectrum above the end of the Franck−Condon envelope at 9.9 eV.

Conformer-Dependent Chemistry: Experimental Product Branching of the Vinyl Alcohol + OH + O2 Reaction

“…To quantify the amount of VA formed we added 1 sccm of calibration gas containing 1% propene to the flow through the reactor and measured the m / z 42 (propene) and m / z 44 signal (VA) at 10.0 eV. Using the known PI cross sections of propene and VA , and the known concentration of propene, the concentration of VA can be determined using eq . N V A = N P · S V A S P · σ P σ V A · α P α V A N VA and N P are the number densities of VA and propene molecules, S represents the measured ion signals, σ represents the photoionization cross sections, and α values are correction factors that account for instrument-specific mass-dependent detection efficiencies. The VA concentration for the used pyrolysis condition was N VA = 6.8 ± 1.7 × 10 12 cm –3 .…”

“…We use a calibration gas with known quantities (1% each) of ethylene, propene, and 1-butene in Ar to calibrate the mass spectrometer and the photon energy by comparing the observed onset and shape of the photoionization (PI) spectrum of propene with its known spectrum. 32 In our previous work measuring the absolute photoionization cross section of VA, 29 we synthesized VA in situ by pyrolysis of 2-Chloroethanol (2CE) according to the methods described by Joo et al 26 The pyrolysis cell was ∼2 m upstream from our quartz reactor, and the product gases were delivered to the reactor through polytetrafluoroethylene (PTFE) tubing. This setup works well for gas mixes with large 2CE mole fractions created by bubbling He through liquid 2CE at 100 Torr pressure.…”

“…More recently highresolution FTIR, 26 photoion 8 and far-IR spectra of anti-27 and syn-VA 28 have been reported. In a recent paper, we reported the absolute photoionization cross section of VA enabling quantitative reaction studies of VA. 29 To our knowledge, the VA + OH + O 2 reaction has not previously been investigated experimentally. To gain insight into the product branching ratios and evaluate whether VA could be a major source of FA in the troposphere, we report here the first experimental investigation of the VA + OH + O 2 reaction as well as the absolute photoionization cross section of one of the reaction products, GA. We find that GA, not FA, is the main product of this reaction, supporting the theoretical findings of Lei et al 12 that there is a significant conformational reactivity difference for the two VA conformers and that under atmospheric conditions mainly GA is formed due to the much larger abundance of syn-over anti-VA. We also perform kinetic modeling calculations and find good agreement with the experimental results.…”

Characterization of the Coriolis Coupled Far-Infrared Bands of syn-Vinyl Alcohol

“…The elemental abundance of oxygen in Earth’s atmosphere is considerably greater than that of Titan, which makes for a more reactive environment. While VA is expected to play an important role in the chemistry of Earth’s atmosphere, , its lifetime is expected to be very short (∼4 h), making in situ measurements of this chemical intermediate difficult. We note that two stable products that are thought to be produced from VA’s reactive decomposition, i.e., formic acid and glycolaldehyde, have been directly observed in Earth’s atmosphere. , …”

Gas phase synthesis of the C40 nano bowl C40H10

“…Overall, combining the PIE curves and ms-TPE spectra analyses provides compelling evidence for the formation of at least benzocorannulene from the reaction of corannulenyl radicals with vinylacetylene. It shall be highlighted that the combined extraction of PIE and ms-TPES data represents an authenticated approach to identify complex organic molecules as demonstrated at state-of-the-art VUV beamlines at Soleil (France) [38][39][40] , the Swiss Light Source (Switzerland) [41][42][43] , and the Advanced Light Source (US) 44,45 .…”