Ultraviolet absorption and laser-induced fluorescence of shock-heated acetylene

Zabeti, S.; Fikri, Mustapha; Schulz, Christof

doi:10.1016/j.proci.2016.05.018

Cited by 4 publications

(1 citation statement)

References 35 publications

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“…Alternatively, absorption measurements with broadband light sources have been used for multi-species detection, but typical single-path absorption schemes provided limited sensitivity and selectivity [8][9][10]. In contrast, ultrasensitive broadband absorption techniques, such as intracavity absorption spectroscopy (ICAS), are limited in time resolution [11].…”

Section: Introductionmentioning

confidence: 99%

Monitoring formaldehyde in a shock tube with a fast dual-comb spectrometer operating in the spectral range of 1740–1790 cm–1

Fjodorow

Allmendinger²,

Horvath³

et al. 2020

Appl. Phys. B

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A dual-frequency-comb spectrometer based on two quantum-cascade lasers is applied to kinetics studies of formaldehyde (HCHO) in a shock tube. Multispectral absorption measurements are carried out in a broad spectral range of 1740–1790 cm–1 at temperatures of 800–1500 K and pressures of 2–3 bar. The formation of HCHO from thermal decomposition of 1,3,5-trioxane (C3H6O3, 0.9% diluted in argon) and the subsequent oxidation of formaldehyde is monitored with a time resolution of 4 µs. The rate coefficient of the decomposition of C3H6O3 (i.e., HCHO formation) is found to be k1 = 6.0 × 1015 exp(− 205.58 kJ mol−1/RT) s–1. For the oxidation studies, mixtures of 0.36% C3H6O3 and 1% O2 in argon are used. The information of all laser lines, along with the consideration of individual signal variance of each line, is utilized for kinetic and spectral analysis. The experimental kinetic profiles of HCHO are compared with simulations based on the mechanisms of Zhou et al. (Combust Flame, 197:423–438, 2018) and Cai and Pitsch (Combust Flame, 162:1623–1637, 2015).

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Section: Introductionmentioning

confidence: 99%

Monitoring formaldehyde in a shock tube with a fast dual-comb spectrometer operating in the spectral range of 1740–1790 cm–1

Fjodorow

Allmendinger²,

Horvath³

et al. 2020

Appl. Phys. B

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In situ characterisation of absorbing species in stationary premixed flat flames using UV–Vis absorption spectroscopy

2021

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A one-dimensional premixed ethylene–air flame is investigated regarding the presence of various combustion intermediates and products relevant for the formation of carbonaceous particles for various equivalence ratios and spatial positions using in situ UV–Vis absorption spectroscopy. A laser driven light source in combination with a fast spectrometer allow to record absorption spectra at a high rate required for practical combustion devices. The approach is coupled with a least squares regression procedure using a database of several absorbing species in the flame. To account for the high temperature flame conditions, the absorption spectra are convoluted by a simplified Maxwell–Boltzmann distribution model. While the approach is based on several assumptions and a verification requires future detailed intercomparison with other techniques, a first semi-quantitative evaluation can be obtained. This novel approach opens a potential route to the in situ measurement of the evolution of polycyclic aromatic hydrocarbons (PAHs) in flames.

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High-temperature measurements of acetylene VUV absorption cross sections and application to warm exoplanet atmospheres

Fleury,

Poveda,

Benilan

et al. 2025

A&A

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Most observed exoplanets have high equilibrium temperatures (T$_ eq $ > 500 K). Understanding the chemistry of their atmospheres and interpreting their observations requires the use of chemical kinetic models including photochemistry. The thermal dependence of the vacuum ultraviolet (VUV) absorption cross sections of molecules used in these models is poorly known at high temperatures, leading to uncertainties in the resulting abundance profiles. The aim of our work is to study experimentally the thermal dependence of VUV absorption cross sections of molecules of interest for exoplanet atmospheres and provide accurate data for use in atmospheric models. This study focuses on acetylene (C$_ $H$_ We measured absorption cross sections of C$_ $H$_ $ at seven temperatures ranging from 296 to 773 K recorded in the 115-230 nm spectral domain using VUV spectroscopy and synchrotron radiation. These data were used in our 1D thermo-photochemical model, to assess their impact on the predicted composition of a generic hot Jupiter-like exoplanet atmosphere. The absolute absorption cross sections of C$_ $H$_ $ increase with temperature. This increase is relatively constant from 115 to 185 nm and rises sharply from 185 to 230 nm. The abundance profile of C$_ $H$_ $ calculated using the model shows a slight variation, with a maximum decrease of 40<!PCT!> near 5 times 10$^ $ bar, when using C$_ $H$_ $ absorption cross sections measured at 773 K compared to those at 296 K. This is explained by the absorption, higher in the atmosphere, of the actinic flux from 150 to 230 nm due to the increase in the C$_ $H$_ $ absorption in this spectral range. This change also impacts the abundance profiles of other by-products such as methane (CH$_ $) and ethylene (C$_ $H$_ We present the first experimental measurements of the VUV absorption cross sections of C$_ $H$_ $ at high temperatures. Similar studies of other major species are needed to improve our understanding of exoplanet atmospheres.

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Ultraviolet absorption and laser-induced fluorescence of shock-heated acetylene

Cited by 4 publications

References 35 publications

Monitoring formaldehyde in a shock tube with a fast dual-comb spectrometer operating in the spectral range of 1740–1790 cm–1

Monitoring formaldehyde in a shock tube with a fast dual-comb spectrometer operating in the spectral range of 1740–1790 cm–1

In situ characterisation of absorbing species in stationary premixed flat flames using UV–Vis absorption spectroscopy

High-temperature measurements of acetylene VUV absorption cross sections and application to warm exoplanet atmospheres

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