Analysis and predictions of the vibronic spectrum of the ethynyl radical C2H by ab initio methods

Perić, Miljenko; Peyerimhoff, Sigrid D.; Buenker, Robert J.

doi:10.1007/bf01426704

Cited by 67 publications

(36 citation statements)

References 81 publications

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“…For absorption, the molecules were included in a smeared-line approximation, appropriate for white dwarfs due to the high pressure. For C2H, transitions at 9500 cm -1 (= 1.05 μιη) and 5500 cm" 1 (= 1.82 μιη) calculated by Reimers et al (1985), and transitions at 1.78 μπι, 1.81 μιη and 2.61 μηι calculated by Peric et al (1992) with ab initio methods, have been included in our calculations. relevant for LHS1126.…”

Section: Model Atmospheresmentioning

confidence: 99%

Carbon and Hydrocarbon Molecules in Very Cool White Dwarfs

Aslan¹,

Bues²

2000

Symp. - Int. Astron. Union

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Abstract. We report on our investigations in progress on the importance of polyatomic molecules -especially of carbon and hydrocarbon -in the atmospheres of very cool helium-rich white dwarfs. For two sets of abundance ratios, model atmospheres with T e ff = 5000K, logg = 8.0 have been computed and the dependence of C3, C2H and C2H2 on abundance variations of H/He, C/He, O/He and N/He has been calculated in detail, with the absorption of carbon molecules included quantitatively. We discuss the possibility that C2H features can explain the observed IR flux deficiency for LHS1126 at 1.6/rni and 2.0-2.3μια.

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Section: Model Atmospheresmentioning

confidence: 99%

Carbon and Hydrocarbon Molecules in Very Cool White Dwarfs

Aslan¹,

Bues²

2000

Symp. - Int. Astron. Union

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“…Perić et al (41). Yan and Amano proposed assignments for The molecular parameters of the ground vibrational state the bands below 4700 cm 01 (28).…”

Section: Introductionmentioning

confidence: 98%

Faraday Laser Magnetic Resonance Spectroscopy of Vibrationally Excited C2H

Pfelzer

Havenith

Perić

et al. 1996

Journal of Molecular Spectroscopy

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The gas phase spectrum of the C 2 H radical in the region between 3191 and 3342 cm 01 has been studied using a Faraday LMR spectrometer with a CO overtone laser. The C 2 H molecules were produced in an electric dc glow discharge of normal type containing a mixture of helium, acetylene, and hydrogen. We observed two bands of the X 2 S / r A 2 P electronic transition with origins at 3321 and 3229 cm 01 . The lower level of both bands was the first excited bending level of the electronic ground state X. The upper levels were assigned to two 2 P vibronic levels with term values of 3693 and 3600 cm 01 , respectively. They correspond to mixtures of vibrationally excited levels of the X electronic state with the lowest vibronic level of the first excited electronic state A. From the analysis of the spectra we could determine the orbital g factors of the upper levels. These parameters are a very sensitive measure for the mixing between the X and A electronic states. The experimentally derived values were compared with theoretical values, obtained by ab initio calculations, and could be explained by the theoretical model using an improved energy distance between the X and A states. ᭧

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“…Perić et al 42 made a state-of-the-art calculation of the vibronic states up to approximately 5000 cm −1 in 1992, and were able to identify the vibronic levels observed to that time. Later, Tarroni and Carter 43,44 reported more accurate calculations based on variational solutions of the nuclear motion on the coupled high level ab initio potential energy surfaces.…”

Section: Introductionmentioning

confidence: 99%

The near-infrared spectrum of ethynyl radical

Hall

Sears

2016

J. Chem. Phys.

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Transient diode laser absorption spectroscopy has been used to measure three strong vibronic bands in the near infrared spectrum of the C 2 H, ethynyl, radical not previously observed in the gas phase. The radical was produced by ultraviolet excimer laser photolysis of either acetylene or (1,1,1)-trifluoropropyne in a slowly flowing sample of the precursor diluted in inert gas, and the spectral resolution was Doppler- (2004)), the vibronic character of these levels was also assigned. The observed states contain both X 2 Σ + and A 2 Π electronic character. Several local rotational level perturbations were observed in the excited states. Kinetic measurements of the time-evolution of the ground state populations following collisional relaxation and reactive loss of the radicals formed in a hot, nonthermal, population distribution were made using some of the strong rotational lines observed. The case of C 2 H may be a good place to investigate the behavior at intermediate pressures of inert colliders, where the competition between relaxation and reaction can be tuned and observed to compare with master equation models, rather than deliberately suppressed to measure thermal rate constants.

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Analysis and predictions of the vibronic spectrum of the ethynyl radical C2H by ab initio methods

Cited by 67 publications

References 81 publications

Carbon and Hydrocarbon Molecules in Very Cool White Dwarfs

Carbon and Hydrocarbon Molecules in Very Cool White Dwarfs

Faraday Laser Magnetic Resonance Spectroscopy of Vibrationally Excited C2H

The near-infrared spectrum of ethynyl radical

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