A new linelist for the A3Π–<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:mrow><mml:msup><mml:mi>X</mml:mi><mml:mn>3</mml:mn></mml:msup><mml:msup><mml:mstyle mathvariant="normal"><mml:mi>Σ</mml:mi></mml:mstyle><mml:mo>−</mml:mo></mml:msup></mml:mrow></mml:math> transition of the NH free radical

Fernando, Anton; Bernath, P. F.; Hodges, James N.; Masseron, T.

doi:10.1016/j.jqsrt.2018.05.021

Cited by 35 publications

(33 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thanks to the combination of LIF and CRDS techniques, the NH profile in the stoichiometric flame could be measured with a peak mole fraction value as low as 18 ppb. The accuracy of the rotational absorption line strength was estimated to be ±10%, in agreement with the estimated error reported by [21]. Finally, the accuracy of the NH mole fraction determination was estimated to be ±20%, neglecting the possible spatial inhomogeneity of the NH distribution.…”

Section: Mole Fraction Profiles Of Nh By Crdssupporting

confidence: 83%

Quantitative NH measurements by using laser-based diagnostics in low-pressure flames

Lamoureux

Gasnot

Desgroux

2019

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

NH is a key short-lived radical involved in the prompt-NO formation. Quantification of NH is thus particularly important for testing the NO kinetic mechanisms. However, quantitative measurements of native NH in hydrocarbon/oxygen/nitrogen flames remain very scarce. Therefore, in this work, the mole fractions of native NH were obtained using a combination of laser-based diagnostics; Laser Induced Fluorescence (LIF) and Cavity Ring-Down Spectroscopy (CRDS). The NH species was probed after exciting the transition R 1 (6) in the A 3 Π-X 3 Σ -(0-0) system at 333.9 nm. The mole fraction profiles of NH were successfully obtained in premixed low-pressure flames of CH 4 /O 2 /N 2 and C 2 H 2 /O 2 /N 2 at two equivalence ratios of 1.00 and 1.25. The estimated detection limit for the NH radical was around 4.5×10 8 molecule cm -3 (i.e. 2 ppb in mole fraction at 1600 K), which is nearly 2 orders of magnitude lower than previous values reported in the literature. These new experimental results were compared with predictions by a recently developed NO model (namely NOMecha2.0). In the case of the CH 4 flames, a satisfying agreement between the experiment and model was observed. However, in the case of the C 2 H 2 flames, some discrepancies were observed.Model analysis has highlighted the importance of the HCCO radicals in the NH formation through the HCNO HNCO NH 2 reactions pathway. Modification of the rate constant values of the reactions C 2 H 2 +O and HCCO+O 2 , which are key reactions for both the acetylene laminar flame speed and the HCCO predictions, has enabled the model to satisfactorily predict the experimental NH and NO profiles also in the C 2 H 2 flames.

show abstract

Section: Mole Fraction Profiles Of Nh By Crdssupporting

confidence: 83%

Quantitative NH measurements by using laser-based diagnostics in low-pressure flames

Lamoureux

Gasnot

Desgroux

2019

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

show abstract

“…A number of diatomic species have line lists provided by the MoLLIST website [82] . These have been incorporated into the Ex-oMol database, which now includes empirically-derived line lists for the following species [83] : CH [139] ; NH [140][141][142] ; OH [143] ; AlCl [144] ; AlF [144] ; OH + [145,146] ;CaF [147] ; MgF [148] ; KF and NaF [149] ; LiCl and LiF [150] ; MgH [151] ; TiH [152] ; CrH [153] ; FeH [154] ; CP [157] ; CN [158] ; and CaH [160,161] . See Table 2 for further details.…”

Section: Mollist Speciesmentioning

confidence: 99%

The 2020 release of the ExoMol database: Molecular line lists for exoplanet and other hot atmospheres

Tennyson

Yurchenko

Al-Refaie

et al. 2020

Journal of Quantitative Spectroscopy and Radiative Transfer

210

161

View full text Add to dashboard Cite

The ExoMol database ( www.exomol.com ) provides molecular data for spectroscopic studies of hot atmospheres. While the data are intended for studies of exoplanets and other astronomical bodies, the dataset is widely applicable. The basic form of the database is extensive line lists; these are supplemented with partition functions, state lifetimes, cooling functions, Landé g-factors, temperature-dependent cross sections, opacities, pressure broadening parameters, k -coefficients and dipoles. This paper presents the latest release of the database which has been expanded to consider 80 molecules and 190 isotopologues totaling over 700 billion transitions. While the spectroscopic data are concentrated at infrared and visible wavelengths, ultraviolet transitions are being increasingly considered in response to requests from observers. The core of the database comes from the ExoMol project which primarily uses theoretical methods, albeit usually fine-tuned to reproduce laboratory spectra, to generate very extensive line lists for studies of hot bodies. The data have recently been supplemented by line lists derived from direct laboratory observations, albeit usually with the use of ab initio transition intensities. A major push in the new release is towards accurate characterisation of transition frequencies for use in high resolution studies of exoplanets and other bodies.

show abstract

“…As our simulations benefit from chemical composition abundances calculated for disequilibrium chemistry, we additionally included opacities for abundant radicals present in the upper atmosphere from the photolysis of major molecules. These include OH (Yousefi et al 2018), CH (Masseron et al 2014), NH (Fernando et al 2018), SH (Gorman et al 2019 and CN (Brooke et al 2014). The cross sections of these radicals present strong absorption bands at visible wavelengths (Fig.…”

Section: Gaseous Opacitiesmentioning

confidence: 99%

Impact of photochemical hazes and gases on exoplanet atmospheric thermal structure

Lavvas

Arfaux

2021

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We investigate the impact of photochemical hazes and disequilibrium gases on the thermal structure of hot-Jupiters, using a detailed 1-D radiative-convective model. We find that the inclusion of photochemical hazes results in major heating of the upper and cooling of the lower atmosphere. Sulphur containing species, such as SH, S2 and S3 provide significant opacity in the middle atmosphere and lead to local heating near 1 mbar, while OH, CH, NH, and CN radicals produced by the photochemistry affect the thermal structure near 1 μbar. Furthermore we show that the modifications on the thermal structure from photochemical gases and hazes can have important ramifications for the interpretation of transit observations. Specifically, our study for the hazy HD 189733 b shows that the hotter upper atmosphere resulting from the inclusion of photochemical haze opacity imposes an expansion of the atmosphere, thus a steeper transit signature in the UV-Visible part of the spectrum. In addition, the temperature changes in the photosphere also affect the secondary eclipse spectrum. For HD 209458 b we find that a small haze opacity could be present in this atmosphere, at pressures below 1 mbar, which could be a result of both photochemical hazes and condensates. Our results motivate the inclusion of radiative feedback from photochemical hazes in general circulation models for a proper evaluation of atmospheric dynamics.

show abstract

A new linelist for the A3Π–X3Σ− transition of the NH free radical

Cited by 35 publications

References 33 publications

Quantitative NH measurements by using laser-based diagnostics in low-pressure flames

Quantitative NH measurements by using laser-based diagnostics in low-pressure flames

The 2020 release of the ExoMol database: Molecular line lists for exoplanet and other hot atmospheres

Impact of photochemical hazes and gases on exoplanet atmospheric thermal structure

Contact Info

Product

Resources

About