Band analysis of the Swan system (d3Πg-a3Πu) of 13C2 and 12C13C molecules

Pešić, D. S.; Vujisić, B.R.; Rakotoarijimy, D.

doi:10.1016/0022-2852(83)90085-1

Cited by 10 publications

(5 citation statements)

References 8 publications

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“…The algorithm is similar to previously reported [33], except that a few changes have been implemented to improve the fitting. First, instead of calculating all the theoretical rotational-line positions through the vibrational and rotational constants of the molecules, experimentally reported rotational structures [43][44][45][46] are used throughout whenever available. The recent compilations of C 2 and CN rotational structures by Brooke et al [43] and Ram et al [44], respectively, are particularly useful.…”

Section: Isotopic Analysis From C 2 and Cn Molecular Emissionmentioning

confidence: 99%

“…A set of theoretical spectra for 12 C 12 C and 13 C 12 C (denoted as and respectively) were generated with experimental reported wavelengths () [43,45], whenever available, for each rotational component in the C A similar procedure was used for fitting the CN B 2  + -X 2  + (0-1) band; a set of theoretical spectra for 12 C 14 N and 13 C 14 N (denoted as and respectively) were generated with experimentally determined rotational structures [44,46], and the fitting algorithm locates the relative number densities of 12 C 14 N and 13 C 14 N in the B 2  + (v = 0) state (denoted as  CN and  CN , respectively) from the experimental spectra, , through…”

Section: Isotopic Analysis From C 2 and Cn Molecular Emissionmentioning

confidence: 99%

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Elucidation of C2 and CN formation mechanisms in laser-induced plasmas through correlation analysis of carbon isotopic ratio

Dong

Chan

Mao

et al. 2014

Spectrochimica Acta Part B: Atomic Spectroscopy

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Laser Ablation Molecular Isotopic Spectrometry (LAMIS) was recently reported for rapid isotopic analysis by measuring molecular emission from laser-induced plasmas at atmospheric pressure. With 13 C-labelled benzoic acid as a model sample, this research utilized the LAMIS approach to clarify the formation mechanisms of C 2 and CN molecules during laser ablation of organic materials. Because the isotopic ratios in the molecular bands could deviate from statistical distribution depending on their formation pathways, the dominant mechanism can be identified through a comparison of the experimental observed isotopic patterns in the molecular emission with the theoretical statistical pattern. For C 2 formation, the experimental 12 C 12 C / 13 C 12 C ratios support a recombination mechanism through atomic carbon at early delay time but also indicate the presence of other operating mechanisms as the plasma evolves; it is proposed that some of the C 2 molecules are released directly from the aromatic ring of the sample as molecular fragments. In contrast, the temporal profiles in the 12 C / 13 C ratios derived from CN emission exhibited opposite behavior with those derived from C 2 emission, which unambiguously refutes mechanisms that require C 2 as a precursor for CN formation; CN formation likely involves atomic carbon or species with a single carbon atom.

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Section: Isotopic Analysis From C 2 and Cn Molecular Emissionmentioning

confidence: 99%

Section: Isotopic Analysis From C 2 and Cn Molecular Emissionmentioning

confidence: 99%

Elucidation of C2 and CN formation mechanisms in laser-induced plasmas through correlation analysis of carbon isotopic ratio

Dong

Chan

Mao

et al. 2014

Spectrochimica Acta Part B: Atomic Spectroscopy

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“…The wavelength shift between a 12 C 13 C line and the corresponding 12 C 2 line is calculated using standard formulae for the vibrational and rotational shifts (Herzberg & Phillips 1948;Stawikowski & Greenstein 1964;Russo et al 2011). Predictions for the bandhead wavelength shifts were checked against the measurements by Pesic et al (1983).…”

Section: Observationsmentioning

confidence: 99%

THE GALACTIC R CORONAE BOREALIS STARS: THE C₂SWAN BANDS, THE CARBON PROBLEM, AND THE¹²C/¹³C RATIO

Hema

Pandey

Lambert

2012

ApJ

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Observed spectra of R Coronae Borealis (RCB) and hydrogen-deficient carbon (HdC) stars are analyzed by synthesizing the C 2 Swan bands (1,0), (0,0), and (0,1) using our detailed line list and the Uppsala model atmospheres. The (0,1) and (0,0) C 2 bands are used to derive the 12 C abundance, and the (1,0) 12 C 13 C band to determine the 12 C/ 13 C ratios. The carbon abundance derived from the C 2 Swan bands is about the same for the adopted models constructed with different carbon abundances over the range: 8.5 (C/He = 0.1%), to 10.5 (C/He = 10%). Carbon abundances derived from C i lines are about a factor of 4 lower than the carbon abundance of the adopted model atmosphere over the same C/He interval, as reported by Asplund et al. (2000), who dubbed the mismatch between adopted and derived C abundance the 'carbon problem'. In principle, the carbon abundances obtained from C 2 Swan bands and that assumed for the model atmosphere can be equated for a particular choice of C/He that varies from star to star. Then, the carbon problem for C 2 bands is eliminated. However, such C/He ratios are in general less than those of the EHe stars, the seemingly natural relatives to the RCB and HdC stars. A more likely solution to the C 2 carbon problem may lie in a modification of the model atmosphere's temperature structure. The derived carbon abundances and the 12 C/ 13 C ratios are discussed in light of the double degenerate (DD) and the final flash (FF) scenarios. Subject headings: Stars -abundances, Isotopic ratio-carbon, evolution of stars cross-dispersed echelle spectrometer (Rao et al. 2005) and a 4K × 4K CCD are at a resolving power of about 30,000. Spectrum synthesisOur analysis of the high-resolution spectra proceeds by fitting synthetic spectra to the observed spectra in several bandpasses providing lines of the C 2 Swan system. For the synthesis of the C 2 Swan bands, we use model atmospheres and as complete a line list as possible. In the following subsections we introduce the line lists for the C 2 Swan bands and the atomic lines blended with the C 2 bands and, finally, the procedure for computing the synthetic spectra. The Swan bandsThe C 2 Swan bands are detectable in all but the hottest RCB stars. They are not seen in either V3795 Sgr or XX Cam with effective temperatures of 8000 K and 7250 K, respectively. In our sample, they are first detectable in VZ Sgr at T eff = 7000 K. The bands are very strong in the coolest RCB stars like U Aqr and the HdC stars. The leading bands of the three sequences: ∆ν = +1, 0, and -1 are each considered. All bands have blue-degraded bandheads. The (0,0) band of the 12 C 2 molecule with its head at 5165Å is the strongest band of the entire Swan system. The (1,0) and (0,1) bandheads are at 4737Å and 5636Å, respectively. All three bands are synthesized using detailed line lists including the blending atomic lines and appropriate model atmospheres. The (1,0), (0,0), and (0,1) 12 C 2 bands are used to determine the C abundance and, hence, to assess the carbon problem. The (0,1) band is...

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“…This was corrected by the infrared studies of Chauville, Maillard, and Mantz12 from the previously accepted value of 13 310 cm"1.6 Recent spectroscopic studies of Davis et al have measured improved molecular parameters of 12C2. 13 Pesic et al 14 observed the Swan bands of 13C2 and 12C13C and determined isotope effects upon band origins and molecular vibrational and rotational parameters. A series of high-resolution Fourier transform spectroscopic studies of 12C2, 13C2, and 12C13C were made by Amiot and co-workers.…”

Section: C2 Moleculementioning

confidence: 99%

Carbon molecules, ions, and clusters

Weltner¹,

Zee²

1989

Chem. Rev.

850

466

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Band analysis of the Swan system (d3Πg-a3Πu) of 13C2 and 12C13C molecules

Cited by 10 publications

References 8 publications

Elucidation of C2 and CN formation mechanisms in laser-induced plasmas through correlation analysis of carbon isotopic ratio

Elucidation of C2 and CN formation mechanisms in laser-induced plasmas through correlation analysis of carbon isotopic ratio

THE GALACTIC R CORONAE BOREALIS STARS: THE C₂SWAN BANDS, THE CARBON PROBLEM, AND THE¹²C/¹³C RATIO

Carbon molecules, ions, and clusters

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Band analysis of the Swan system (d3Πg-a3Πu) of 13C2 and 12C13C molecules

Cited by 10 publications

References 8 publications

Elucidation of C2 and CN formation mechanisms in laser-induced plasmas through correlation analysis of carbon isotopic ratio

Elucidation of C2 and CN formation mechanisms in laser-induced plasmas through correlation analysis of carbon isotopic ratio

THE GALACTIC R CORONAE BOREALIS STARS: THE C2SWAN BANDS, THE CARBON PROBLEM, AND THE12C/13C RATIO

Carbon molecules, ions, and clusters

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THE GALACTIC R CORONAE BOREALIS STARS: THE C₂SWAN BANDS, THE CARBON PROBLEM, AND THE¹²C/¹³C RATIO