Vibrational spectra of crystalline dimethyl ethers

Allan, A.; McKean, D.C.; Perchard, J. P.; Josien, Marie‐Louise

doi:10.1016/0584-8539(71)80092-2

Cited by 60 publications

(22 citation statements)

References 18 publications

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“…B.24 are difficult. However, four separated bands I-IV are observed here and are briefly discussed relying on bands assignments by Allan et al [47], Blom et al [48], and Hameka [49]: I. 2750-3100 cm À1 : This is the CH-stretching region that is mainly constituted of five strongly polarized Raman peaks at 2823 cm À1 , 2872 cm À1 , 2926 cm À1 , 2963 cm À1 and 2999 cm À1 as reported by Blom et al [48].…”

Section: A6 Other Possible Sources Of Experimental Errorssupporting

confidence: 70%

“…Here, two Raman peaks are most notably because of their apparent change in relative signal intensities at higher temperature. First, the dominating peak in cold gas here observed at 2820 cm À1 , which probably results from Fermi resonance of symmetric out-of-plane (C-O-C plane) CH 2 stretch and in-plane CH stretch vibrations as stated by Allan et al [47]. Second, the peak at 2926 cm À1 which is very likely assigned to the asymmetric CH 2 out-of-plane stretch mode (Allan et al).…”

Section: A6 Other Possible Sources Of Experimental Errorsmentioning

confidence: 54%

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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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Section: A6 Other Possible Sources Of Experimental Errorssupporting

confidence: 70%

Section: A6 Other Possible Sources Of Experimental Errorsmentioning

confidence: 54%

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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show abstract

“…Instead, we have at least two bands in the experimental spectrum in the 2900-2750 cm À1 region. This is a manifestation of the well-known Fermi resonance between n s CH 3 and overtones of deformation dCH 3 modes, which usually takes place in the vibrational spectra of compounds containing methoxy groups [18,19].…”

Section: Resultsmentioning

confidence: 98%

DFT predictions of vibrational spectra of titanium tetramethoxide oligomers and the structure of titanium tetraalkoxides in liquid and solid phases

Ignatyev

Montejo

González

2009

Vibrational Spectroscopy

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“…Identification of vibrational modes of the three species studied here is realized by comparison with available spectra from liquid and solid state literature (Plyler 1952;Evans & Bernstein 1956; Barnes & Hallam 1970;Allan et al 1971; A35, page 3 of 43 Hollenstein & Günthard 1971;Mikawa et al 1971;Coussan et al 1998). Optical effects such as longitudinal optical-transverse optical (LO-TO) splitting and particle shape effects are not explicitly taken into account.…”

Section: Analysis Protocolmentioning

confidence: 99%

Infrared spectra of complex organic molecules in astronomically relevant ice matrices. III. Methyl formate and its tentative solid-state detection

Scheltinga

Marcandalli

McClure

et al. 2021

A&A

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Context. Infrared spectroscopy of star and planet forming regions is at the dawn of a new age with the upcoming James Webb Space Telescope (JWST). Its high resolution and unprecedented sensitivity allows us to probe the chemical complexity of planet forming regions, such as dense clouds, embedded protostars, and protoplanetary disks, both in the solid state and gas phase. In support of these observations, laboratory spectra are required to identify complex organic molecules in the ices that cover the dust grains in these regions. Aims. This study aims to provide the necessary reference spectra to firmly detect methyl formate (HCOOCH3) in the different evolutionary stages of star and planet forming regions. Methyl formate is mixed in astronomically relevant matrices, and the peak positions, full width at half maximum, and relative band intensities are characterized for different temperatures to provide an analytical tool for astronomers. Methods. Methyl formate was deposited at 15 Kelvin on a cryogenically cooled infrared transmissive window under high-vacuum conditions. Specifically, methyl formate was deposited pure and mixed with CO, H2CO, CH3OH, H2O, and CO:H2CO:CH3OH combined. The sample was linearly heated until all solid-state constituents were desorbed. Throughout the experiment, infrared spectra were acquired with a Fourier transform infrared spectrometer in the range from 4000 to 500 cm−1 (2.5–20 μm) at a spectral resolution of 0.5 cm−1. Results. We present the characterization of five solid-state methyl formate vibrational modes in pure and astronomically relevant ice matrices. The five selected vibrational modes, namely the C=O stretch (5.804 μm), the C−O stretch (8.256 μm), CH3 rocking (8.582 μm), O−CH3 stretching (10.98 μm), and OCO deformation (13.02 μm), are best suited for a JWST identification of methyl formate. For each of these vibrational modes, and each of the mixtures the temperature versus spectra heatmaps, peak position versus full width at half maximum and relative band intensities are given. All spectra are publicly available on the Leiden Ice Database. Additionally, the acquired reference spectra of methyl formate are compared with archival Spitzer observations of HH 46. A tentative detection of methyl formate provides an upper limit to the column density of 1.7 × 1017 cm−2, corresponding to an upper limit relative to water of ≤2.2% and ≤40% with respect to methanol.

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Vibrational spectra of crystalline dimethyl ethers

Cited by 60 publications

References 18 publications

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

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

DFT predictions of vibrational spectra of titanium tetramethoxide oligomers and the structure of titanium tetraalkoxides in liquid and solid phases

Infrared spectra of complex organic molecules in astronomically relevant ice matrices. III. Methyl formate and its tentative solid-state detection

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