Resonance Raman spectroscopy of the methyl radical

Kelly, Peter B.; Westre, S. G.

doi:10.1016/0009-2614(88)85284-9

Cited by 39 publications

(28 citation statements)

References 16 publications

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“…The planarity was a subject of controversy partly because of the rather small frequency (606 cm À1 ) of the umbrella (OPLA) vibration ( 2 ) that had been viewed as an indication of nonplanar geometry until the planarity was confirmed spectroscopically by Yamada, Hirota, and Kawaguchi [210]. The frequency of the symmetric C-H stretch fundamental ( 1 ) was the subject of many spectroscopic studies [211][212][213][214][215]. Those of the umbrella (OPLA) ( 2 ) [210,216,217] and anti-symmetric C-H stretch ( 3 ) [218][219][220][221][222][223] were also measured accurately.…”

Section: Ch 3 (X 2 a 00mentioning

confidence: 98%

Anharmonic vibrational frequencies and vibrationally-averaged structures of key species in hydrocarbon combustion: HCO⁺, HCO, HNO, HOO, HOO^–, CH₃ ⁺, and CH₃

et al. 2009

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A general scheme to predict anharmonic vibrational frequencies and vibrationally-averaged structures and rotational constants of molecules is presented with applications to some key species in hydrocarbon combustion (some also of importance in atmospheric and/or interstellar chemistry): HCO þ , HCO, HNO, HOO, HOO -,CH þ 3 , and CH 3 . A combination of coupled-cluster singles and doubles (CCSD), CCSD with a second-order perturbation correction in the space of triples [CCSD(2) T ] and in the space of triples and quadruples [CCSD(2) TQ ], and a correlation-consistent basis set series has been employed to achieve the complete-correlation, complete-basis-set limits of the potential energy surfaces (PESs) of these species near equilibrium geometries. A new, compact representation of PESs that combines two existing representations, namely, a fourth-order Taylor expansion and numerical values on a rectilinear grid, has been proposed and shown to yield accurate frequencies, when combined with vibrational general-order configuration-interaction method. The predicted frequencies (and the observed in parentheses, when available) of the fundamentals are as follows: 823 3139 (3161) cm À1 in CH 3 . The mean absolute deviation in the predicted frequencies is 11 cm À1 .

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Section: Ch 3 (X 2 a 00mentioning

confidence: 98%

Anharmonic vibrational frequencies and vibrationally-averaged structures of key species in hydrocarbon combustion: HCO⁺, HCO, HNO, HOO, HOO^–, CH₃ ⁺, and CH₃

et al. 2009

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“…The [53], where the channel to monitor the background starts. The relative intensity of the CH 3 -m 1 band has been measured by CARS by Hädrich et al [36] and is one quarter relative to CH 4 .…”

Section: A6 Other Possible Sources Of Experimental Errorsmentioning

confidence: 99%

Raman/Rayleigh scattering and CO-LIF measurements in laminar and turbulent jet flames of dimethyl ether

Fuest

Barlow

Chen

et al. 2012

Combustion and Flame

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To reduce the impact of combustion of fossil fuels on air quality and climate change, dimethyl ether (DME) is a promising alternative diesel fuel candidate. Technical combustion processes, including formation of pollutants, are influenced by turbulence-chemistry interaction. Therefore, accurate prediction by computational combustion models of combustion systems burning DME must account for multiple scalars and scalar gradients. The testing of such models requires detailed experiments. Here a study is presented on the feasibility of simultaneous species and temperature measurements in turbulent dimethyl ether flames, using line-imaged Raman/Rayleigh scattering of the major species H 2 , O 2 , N 2 , CO, CO 2 , H 2 O, C 2 H 6 O and laser induced fluorescence of CO. The measurement system and data evaluation methods developed to investigate methane-air flames are extended to address dimethyl ether flames. The Raman signal intensity and spectral shape of the Raman scattering from dimethyl ether over a range of temperatures are presented, based on measurements in electrically heated flows and laminar jet flames. These data are used to develop an iterative method for data evaluation that allows determination of indispensable crosstalk correction terms for the concentration measurements of O 2 and CO 2. Issues of fluorescence interferences, mainly from C 2 radicals on the fuel-rich side of the reaction zone, and their corrections are discussed. Laminar flame calculations are used to investigate the role of the intermediate species (CH 4 , CH 2 O, C 2 H 4 , C 2 H 2 , C 2 H 6 , CH 3) in the reaction zone. In particular, their effect on the mixture fraction calculation and its relationship to the experimentally determined mixture fraction is examined. The impact of the intermediate species on deviations in concentration and temperature profiles due to species-specific Raman-and Rayleigh scattering cross-sections is demonstrated. Finally, species concentrations and temperature profiles from measurements in a turbulent piloted jet flame of dimethyl ether are shown.

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“…For each normal mode, we give in parentheses its symmetry in the molecular symmetry group D 3h (M) (see Table A state. The experimental value of the m 1 -band origin has been determined as 3002.4 cm À1 from resonance-Raman spectra [46] and as 3004.8 and 3004.4 cm À1 , respectively, in two CARS experiments [26,27]. Further CARS studies [47,48] have produced similar values.…”

Section: Resultsmentioning

confidence: 92%

Non-Resonant Raman Spectra of the Methyl Radical 12ch3 Simulated in Variational Calculations

Adam¹,

Yachmenev²,

Yurchenko³

et al. 2019

Proceedings of the 74th International Symposium on Molecular Spectroscopy

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a b s t r a c tWe report first-principles variational simulation of the non-resonant Raman spectrum for the methyl radical ( 12 CH 3 ) in the electronic ground state. Calculations are based on a high level ab initio potential energy and dipole moment surfaces of CH 3 and employ the accurate variational treatment of the ro-vibrational dynamics implemented in the general code TROVE [S. N. Yurchenko, W. Thiel, and P. Jensen, J. Mol. Spectrosc. 245, 126-140 (2007); A. Yachmenev and S. N. Yurchenko, J. Chem. Phys. 143, 014105 (2015)]. TROVE can be applied to arbitrary molecules of moderate size and we extend here its capabilities towards simulations of Raman spectra. The simulations for CH 3 are found to be in a good agreement with the available experimental data.

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Resonance Raman spectroscopy of the methyl radical

Cited by 39 publications

References 16 publications

Anharmonic vibrational frequencies and vibrationally-averaged structures of key species in hydrocarbon combustion: HCO⁺, HCO, HNO, HOO, HOO^–, CH₃ ⁺, and CH₃

Anharmonic vibrational frequencies and vibrationally-averaged structures of key species in hydrocarbon combustion: HCO⁺, HCO, HNO, HOO, HOO^–, CH₃ ⁺, and CH₃

Raman/Rayleigh scattering and CO-LIF measurements in laminar and turbulent jet flames of dimethyl ether

Non-Resonant Raman Spectra of the Methyl Radical 12ch3 Simulated in Variational Calculations

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Resonance Raman spectroscopy of the methyl radical

Cited by 39 publications

References 16 publications

Anharmonic vibrational frequencies and vibrationally-averaged structures of key species in hydrocarbon combustion: HCO+, HCO, HNO, HOO, HOO–, CH3 +, and CH3

Anharmonic vibrational frequencies and vibrationally-averaged structures of key species in hydrocarbon combustion: HCO+, HCO, HNO, HOO, HOO–, CH3 +, and CH3

Raman/Rayleigh scattering and CO-LIF measurements in laminar and turbulent jet flames of dimethyl ether

Non-Resonant Raman Spectra of the Methyl Radical 12ch3 Simulated in Variational Calculations

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Anharmonic vibrational frequencies and vibrationally-averaged structures of key species in hydrocarbon combustion: HCO⁺, HCO, HNO, HOO, HOO^–, CH₃ ⁺, and CH₃

Anharmonic vibrational frequencies and vibrationally-averaged structures of key species in hydrocarbon combustion: HCO⁺, HCO, HNO, HOO, HOO^–, CH₃ ⁺, and CH₃