Ionization photophysics and spectroscopy of cyanoacetylene

Leach, Sydney; Schwell, Martin; Garcı́a, Gustavo; Bénilan, Y.; Fray, N.; Gazeau, M.‐C.; Gaie-Levrel, François; Champion, Norbert; Guillemin, Jean‐Claude

doi:10.1063/1.4871298

Cited by 19 publications

(10 citation statements)

References 101 publications

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“…displays a comparison of the measured absorption spectrum with theoretically (CAM-B3LYP) predicted vertical electronic excitations departing from theX 1 A 1 ground electronic state. Noteworthy, the spectrum qualitatively resembles that of HC 3 N[32,33]. As can be seen, computations satisfactorily reproduce the observed valence shell transitions (displayed as purple sticks in…”

supporting

confidence: 63%

Excited electronic structure of methylcyanoacetylene probed by VUV Fourier-transform absorption spectroscopy

Lamarre

Gans

Mendes

et al. 2016

Journal of Quantitative Spectroscopy and Radiative Transfer

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International audienceHigh resolution photoabsorption spectrum of gas-phase methylcyanoacetylene (CH3C3N) has been recorded from 44 500 to 130 000 cm−1 at room temperature with a vacuum ultraviolet Fourier-transform spectrometer on the DESIRS synchrotron beamline (SOLEIL). The absolute photoabsorption cross section in this range is reported for the first time. Valence shell transitions and Rydberg series converging to the ground state X˜+E2 of the cation as well as series converging to electronically excited states (A˜+A12 and C˜+) are observed and assigned. Time-dependent density-functional-theory calculations have been performed to support the assignment of the experimental spectrum in the low energy range. A tentative scaling of the previously measured CH3C3N+ ion yield by Lamarre et al. [17] is proposed, based on the comparison of the absorption data above the first ionization potential with the observed autoionization structures

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supporting

confidence: 63%

Excited electronic structure of methylcyanoacetylene probed by VUV Fourier-transform absorption spectroscopy

Lamarre

Gans

Mendes

et al. 2016

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…The masses observed at m=q ¼ 44, 50 and 51 can be assigned without any ambiguity to CD 3 CN, CH 3 Cl and HC 3 N, respectively, comparing the observed ion yields (not shown here) with earlier works [39,40,1].…”

Section: Dissociative Ionization Of Cyanopropynementioning

confidence: 96%

“…Although the chemical and physical properties of HC 3 N have been extensively studied (see for instance Ref. [1] and references therein), cyanopropyne has been much less investigated. Less ubiquitous than HC 3 N, which has been observed in several molecular clouds of the Interstellar Medium (ISM), in Titan and in comets, cyanopropyne was detected in 1984 in the molecular cloud TMC-1 and more recently in Sgr B2 [2,3].…”

Section: Introductionmentioning

confidence: 99%

Photoionization spectroscopy of CH3C3N in the vacuum-ultraviolet range

Lamarre

Falvo

Alcaraz

et al. 2015

Journal of Molecular Spectroscopy

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International audienceUsing vacuum-ultraviolet (VUV) synchrotron radiation, threshold and dissociative photoionization of cyanopropyne (CH3C3N) in the gas phase have been studied from 86 000 cm−1 up to 180 000 cm−1 by recording Threshold-PhotoElectron Spectrum (TPES) and PhotoIon Yield (PIY). Ionization energies of the four lowest electronic states X̃+2E,Ã+2A1,B̃+2E and C̃+ of CH3C3N+ are derived from the TPES with a better accuracy than previously reported. The adiabatic ionization potential of CH3C3N is measured as 86872±20 cm−1. A description of the vibrational structure of these states is proposed leading to the first determination of the vibrational frequencies for most modes. The vibrational assignments of the X̃+ state are supported by density functional theory calculations. In addition, dissociative photoionization spectra have been recorded for several cationic fragments in the range 12–15.5 eV (96 790–125 000 cm−1) and they bring new information on the photophysics of CH3C3N+. Threshold energies for the cationic dissociative channels leading to CH2C3N+, CHC3N+, HC3H+, HCNH+ and CH3+ have been measured for the first time and are compared with quantum chemical calculations

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“…Additionally, a total photoionisation cross section is recorded by Leach et al (2014) and here the remaining photoabsorption cross section was attributed to neutral photodissociation.…”

Section: Hc 3 N -Cyanoacetylenementioning

confidence: 99%

Photodissociation and photoionisation of atoms and molecules of astrophysical interest

Heays

Bosman

Dishoeck

2017

A&A

422

442

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A new collection of photodissociation and photoionisation cross sections for 102 atoms and molecules of astrochemical interest has been assembled, along with a brief review of the basic physical processes involved. These have been used to calculate dissociation and ionisation rates, with uncertainties, in a standard ultraviolet interstellar radiation field (ISRF) and for other wavelength-dependent radiation fields, including cool stellar and solar radiation, Lyman-α dominated radiation, and a cosmic-ray induced ultraviolet flux. The new ISRF rates generally agree within 30% with our previous compilations, with a few notable exceptions. Comparison with other databases such as PHIDRATES is made. The reduction of rates in shielded regions was calculated as a function of dust, molecular and atomic hydrogen, atomic C, and self-shielding column densities. The relative importance of these shielding types depends on the atom or molecule in question and the assumed dust optical properties. All of the new data are publicly available from the Leiden photodissociation and ionisation database. Sensitivity of the calculated rates to variation of temperature and isotope, and uncertainties in measured or calculated cross sections, are tested and discussed. Tests were conducted on the new rates with an interstellar-cloud chemical model, and find general agreement (within a factor of two) in abundances obtained with the previous iteration of the Leiden database assuming an ISRF, and order-of-magnitude variations assuming various kinds of stellar radiation. The newly parameterised dust-shielding factors makes a factor-of-two difference to many atomic and molecular abundances relative to parameters currently in the UDfA and KIDA astrochemical reaction databases. The newly-calculated cosmic-ray induced photodissociation and ionisation rates differ from current standard values up to a factor of 5. Under high temperature and cosmic-ray-flux conditions the new rates alter the equilibrium abundances of abundant dark cloud abundances by up to a factor of two. The partial cross sections for H 2 O and NH 3 photodissociation forming OH, O, NH 2 and NH are also evaluated and lead to radiation-field-dependent branching ratios.

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Ionization photophysics and spectroscopy of cyanoacetylene

Cited by 19 publications

References 101 publications

Excited electronic structure of methylcyanoacetylene probed by VUV Fourier-transform absorption spectroscopy

Excited electronic structure of methylcyanoacetylene probed by VUV Fourier-transform absorption spectroscopy

Photoionization spectroscopy of CH3C3N in the vacuum-ultraviolet range

Photodissociation and photoionisation of atoms and molecules of astrophysical interest

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