Journal of Molecular Spectroscopy最新文献

{"title":"High-temperature line strength and line shape parameters measurements of Ar- and N2-perturbed CO2 lines near 4.18 µm in a shock tube","authors":"Youquan Yang ,&nbsp;Zhimin Peng ,&nbsp;Dao Zheng ,&nbsp;Meng Zhang ,&nbsp;Yanjun Ding ,&nbsp;Yanjun Du","doi":"10.1016/j.jms.2024.111890","DOIUrl":"10.1016/j.jms.2024.111890","url":null,"abstract":"<div><p>Line strengths and line shape parameters of Ar- and N₂-perturbed CO₂ R-branch transitions (82 <span><math><mrow><mo>≤</mo><msup><mrow><mi>J</mi></mrow><mo>″</mo></msup><mo>≤</mo></mrow></math></span> 90) in the <span><math><mrow><msub><mi>ν</mi><mn>3</mn></msub></mrow></math></span> fundamental band were measured in a shock tube from 730 K to 2500 K and pressure below 1.13 atm using laser absorption spectroscopy (LAS). The retrieved absorption curves were fitted with the Voigt and the quadratic speed-dependent Voigt (qSDV) profiles to obtain the line strengths, broadening, and shift coefficients. Line strengths were compared to values in HITEMP, HITRAN2020, and Ames2021 databases, and the HITEMP shows the best agreement with the measured results. Ar- and N₂-broadening and shift coefficients were regressed into the power law and the double power law form to study the temperature dependence of the targeted lines. The speed-dependence parameter <span><math><mrow><msub><mi>a</mi><mi>w</mi></msub></mrow></math></span> was temperature-dependent. The <em>J</em>-dependence of the derived broadening and shift coefficients was discussed. The results of this work will aid the development of the absorption model in the far-wing region and the design of CO₂ LAS sensors for high-temperature measurement.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"400 ","pages":"Article 111890"},"PeriodicalIF":1.4,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139954205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vibrational bands of formaldoxime isotopologue 13CD2NOH in the 280–4000 cm−1 region and rovibrational analysis of its ν12 band by Fourier transform infrared (FTIR) spectroscopy","authors":"A. Jusuf,&nbsp;T.L. Tan","doi":"10.1016/j.jms.2024.111885","DOIUrl":"10.1016/j.jms.2024.111885","url":null,"abstract":"&lt;div&gt;&lt;p&gt;A total of 11 fundamental and 3 overtone bands of the formaldoxime isotopologue &lt;sup&gt;13&lt;/sup&gt;CD&lt;sub&gt;2&lt;/sub&gt;NOH were identified using its Fourier transform infrared (FTIR) spectra which were recorded with a low resolution (0.50 cm&lt;sup&gt;−1&lt;/sup&gt;) in the 500–4000 cm&lt;sup&gt;−1&lt;/sup&gt; region, and high resolution (0.00096 cm&lt;sup&gt;−1&lt;/sup&gt;) in the 280–500 cm&lt;sup&gt;−1&lt;/sup&gt; region. Their relative infrared (IR) band intensities were also measured. Furthermore, a rovibrational analysis of the IR transitions of the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; band of &lt;sup&gt;13&lt;/sup&gt;CD&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;NOH was carried out using its high-resolution FTIR spectrum which was recorded at the Australian Synchrotron. A total of 1077 IR transitions of the &lt;/span&gt;&lt;em&gt;C&lt;/em&gt;-type &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; band were assigned and fitted using the Watson's &lt;em&gt;A&lt;/em&gt;-reduced Hamiltonian in the &lt;em&gt;I&lt;sup&gt;r&lt;/sup&gt;&lt;/em&gt; representation to derive its band center and the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt; = 1 state rovibrational constants up to all 5 quartic centrifugal distortion terms for the first time, with a root-mean-square (rms) deviation of 0.00044 cm&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;. The band center of the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; band of &lt;sup&gt;13&lt;/sup&gt;CD&lt;sub&gt;2&lt;/sub&gt;NOH were found to be 391.054446(36) cm&lt;sup&gt;−1&lt;/sup&gt;. The ground state rovibrational constants up to all 5 quartic terms were determined for the first time by fitting 407 ground state combination differences (GSCDs) derived from the assigned IR transitions of the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; band of &lt;sup&gt;13&lt;/sup&gt;CD&lt;sub&gt;2&lt;/sub&gt;NOH of this work. The rms deviation of the GSCD fit was 0.00040 cm&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;. Additionally, all 3 rotational constants and 5 quartic centrifugal distortion terms of the ground state and 3 rotational constants of the &lt;/span&gt;&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; = 1 state of &lt;sup&gt;13&lt;/sup&gt;CD&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;NOH were computed from theoretical anharmonic calculations at two different levels of theory, B3LYP and MP2 with the cc-pVTZ basis set, for comparison with the experimental results. Close agreement was found for the calculated and experimental rovibrational constants of &lt;/span&gt;&lt;sup&gt;13&lt;/sup&gt;CD&lt;sub&gt;2&lt;/sub&gt;NOH for both ground and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; = 1 states. The vibrational anharmonic frequencies of the 12 fundamental bands of &lt;sup&gt;13&lt;/sup&gt;CD&lt;sub&gt;2&lt;/sub&gt;NOH in the 280–4000 cm&lt;sup&gt;−1&lt;/sup&gt; region, and their IR band intensities were also calculated using B3LYP and MP2 with the cc-pVTZ basis set, and they were compared with the respective experimental data. Finally, the ground state rotational constants and the band center of the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ν&lt;/mi&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"400 ","pages":"Article 111885"},"PeriodicalIF":1.4,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139501513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microwave measurements and structure calculations for a glyoxylic acid – Water complex","authors":"Adam M. Daly,&nbsp;Rhett P. Hill,&nbsp;Myla G. Gonzalez,&nbsp;Stephen G. Kukolich","doi":"10.1016/j.jms.2023.111862","DOIUrl":"https://doi.org/10.1016/j.jms.2023.111862","url":null,"abstract":"<div><p>The microwave spectra for a hydrogen-bonded <em>trans</em>-2 glyoxylic acid–water complex were measured in the 6–16 GHz frequency range using two Flygare-Balle type pulsed beam Fourier transform microwave (FTMW) spectrometers. The rotational constants for the dimer were determined to have the following values: A = 9384.2354(31), B = 1707.63973(73), and C = 1447.44879(56) MHz. The hydrogen bonded structures and rotational constants were calculated for the lowest energy dimglyoxylic acid - water using DFT, MP2 and CCSD calculations with various basis sets. The B3LYP/aug-cc-PVQZ-DG3 calculations yielded rotational constants of A = 9393.59, B = 1713.76, and C = 1453.23 MHz, in very good agreement with experimental values. The calculations show two feasible tunneling motions involving hydrogen atoms in this complex.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"399 ","pages":"Article 111862"},"PeriodicalIF":1.4,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138489844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A spectroscopic investigation of the lowest electronic states of the I2+ cation as a candidate for detecting the time variation of fundamental constants","authors":"Yujie Zhao ,&nbsp;Yali Tian ,&nbsp;Xiaohu He ,&nbsp;Ting Gong ,&nbsp;Xiaocong Sun ,&nbsp;Guqing Guo ,&nbsp;Xuanbing Qiu ,&nbsp;Xiang Yuan ,&nbsp;Jinjun Liu ,&nbsp;Lunhua Deng ,&nbsp;Chuanliang Li","doi":"10.1016/j.jms.2023.111873","DOIUrl":"https://doi.org/10.1016/j.jms.2023.111873","url":null,"abstract":"<div><p>The four lowest Ω substates (<em>X</em>²Π_3/2,g, <em>X</em>²Π_1/2,g, <em>A</em>²Π_3/2,u and <em>A</em>²Π_1/2,u) of the <span><math><mrow><msubsup><mtext>I</mtext><mn>2</mn><mo>+</mo></msubsup></mrow></math></span> cation have been studied by high-precision <em>ab initio</em> calculations in comparison with experimental high-resolution absorption spectra. The potential energy curves were calculated using the multi-reference configuration interaction (MRCI) method and Dirac method, respectively. Rovibrational levels of these electronic states were derived by solving the radial Schrödinger rovibrational equation. Molecular constants were obtained in fitting energy levels to a spectroscopic model. Using the fit spectroscopic constants and newly calculated transition dipole moment matrix elements, line strengths of vibronic bands in the <em>A</em>²Π_3/2,u- <em>X</em>²Π_3/2,g system, as well as Einstein <em>A</em> coefficients for 45 of these bands with <em>ν′</em> = 11–19 and <em>ν′′</em> = 1–5, have been derived. The Einstein <em>A</em> coefficients were used to compute radiative lifetimes of the <em>ν′</em> = 11–19 vibrational levels of the <em>A</em>²Π_3/2,u state. Enhancement factors for detecting the variation of the fine-structure constant (<em>α</em>) and the proton-to-electron mass ratio(<em>µ</em>) using transitions between nearly degenerate rovibronic levels of these low-lying states have been calculated.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"399 ","pages":"Article 111873"},"PeriodicalIF":1.4,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139100532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The microwave spectrum of the low energy conformers of 1-ethylsilacyclopentane","authors":"Josie R. Glenn ,&nbsp;J.E. Isert ,&nbsp;Jacob D. Bethke ,&nbsp;Gamil A. Guirgis ,&nbsp;G.S. Grubbs II","doi":"10.1016/j.jms.2023.111872","DOIUrl":"10.1016/j.jms.2023.111872","url":null,"abstract":"<div><p>The microwave rotational spectrum of 1-ethylsilacyclopentane has been observed using chirped-pulse, Fourier transform microwave spectroscopy and has been reported for the first time. The lowest three energetic conformers were observed and fit to a Watson S semirigid Hamiltonian to within experimental accuracy. The quantum chemical calculations are all within ≈1% of the determined rotational constants, providing confidence that they are accurate representations of the experimental structure. Centrifugal distortion terms <em>D_JK</em> and <em>D_K</em>, although seemingly large, have been determined to be physically meaningful as no apparent evidence such as splittings in the spectrum or transition broadening was observed. A second moment analysis was undertaken and compared to similar silacyclopentanes, but it is not clear if this species follows previously determined trends.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"399 ","pages":"Article 111872"},"PeriodicalIF":1.4,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139021346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the calculated and observed X-X ro-vibrational transition intensities in molecular hydrogen","authors":"V.G. Ushakov ,&nbsp;S.A. Balashev ,&nbsp;E.S. Medvedev","doi":"10.1016/j.jms.2023.111863","DOIUrl":"10.1016/j.jms.2023.111863","url":null,"abstract":"<div><p>The potential-energy and quadrupole-moment functions of the H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> ground electronic state are well known in literature (Komasa et al., 2019; Wolniewicz et al., 1998), and the line list of the vibrational–rotational transitions was calculated (Roueff et al., 2019). In this paper, we analyze the calculated intensities in order to learn how the intensities will change when analytic quadrupole-moment functions fitted to the <em>ab initio</em> and experimental data are used instead of spline-interpolated functions. We found that the use of splines does not deteriorate the intensities and does not lead to nonphysical saturation, as in heavier molecules, owing to the high precision of the <em>ab initio</em> data and the high density of the grid. The accuracy of the calculated intensities is estimated up to high overtones. Extraction of new spectroscopic information from the observational data that supplements the laboratory measurements is performed. The laboratory and observational data do not help increase the quality of the analytic functions. Numerous anomalies resulting from the destructive interference are identified in the calculated line lists, some of them being situated within the recently observed spectral regions, 1.5–<span><math><mrow><mn>2</mn><mo>.</mo><mn>5</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span>. The intensities of these anomalies can be sensitive to the form of the molecular functions as well as to the proton-to-electron mass ratio. In this connection, the similar Le Roy anomalies (Brown and LeRoy, 1973; Le Roy and Vrscay, 1975) also arising due to the destructive interference in the Lyman and Werner systems are discussed.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"399 ","pages":"Article 111863"},"PeriodicalIF":1.4,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138529739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential and kinetic interaction of two internal tops in molecules belonging to C2v(M) molecular symmetry group","authors":"George A. Pitsevich ,&nbsp;Alex E. Malevich ,&nbsp;Uladzimir U. Sapeshka","doi":"10.1016/j.jms.2023.111860","DOIUrl":"https://doi.org/10.1016/j.jms.2023.111860","url":null,"abstract":"<div><p>Fourier analysis of the kinetic and potential interactions of non-coaxial internal tops in the molecules C₆H₄(OH)₂, HO(CH₂)OH, HOOOH, HOSOH, HSSSH, and HSOSH was carried out. It was found that for the all six molecules, in which both tops are characterized by a period 2 <span><math><mi>π</mi></math></span>, the harmonics with a period of <span><math><mi>π</mi></math></span> are dominate, with its contribution to the Fourier representation of potential surfaces increasing in the sequence mentioned above. Contributions of internal tops interactions to the kinetic and potential energies were determined for analyzed molecules. The influence of potential and kinetic interactions of internal tops on 1) the features of tunneling splitting of the ground and excited torsional states of molecules, 2) the landscape of 2D potential energy surfaces, 3) frequencies of fundamental torsional vibrations of hydroxyl and thiol groups, 4) the ratio of trans - and <em>cis</em> - conformer energies is also analyzed.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"399 ","pages":"Article 111860"},"PeriodicalIF":1.4,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138447972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The microwave spectrum of the low energy conformers of 1-ethylsilacyclopentane","authors":"Josie R. Glenn, J.E. Isert, Jacob D. Bethke, Gamil A. Guirgis, G.S. Grubbs II","doi":"10.1016/j.jms.2023.111872","DOIUrl":"https://doi.org/10.1016/j.jms.2023.111872","url":null,"abstract":"<p>The microwave rotational spectrum of 1-ethylsilacyclopentane has been observed using chirped-pulse, Fourier transform microwave spectroscopy and has been reported for the first time. The lowest three energetic conformers were observed and fit to a Watson S semirigid Hamiltonian to within experimental accuracy. The quantum chemical calculations are all within ≈1% of the determined rotational constants, providing confidence that they are accurate representations of the experimental structure. Centrifugal distortion terms <em>D_JK</em> and <em>D_K</em>, although seemingly large, have been determined to be physically meaningful as no apparent evidence such as splittings in the spectrum or transition broadening was observed. A second moment analysis was undertaken and compared to similar silacyclopentanes, but it is not clear if this species follows previously determined trends.</p>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"31 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139022394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Rare Case of Retropharyngeal Abscess in a 3 Month Old Male Infant: Case Report and Review of Literature.","authors":"Lohith Rajanna, Sheetal Raina, Himanshu Chhagan Bayad, Shailendra Tripathi, Omvir Singh Chahar, Ombir Singh","doi":"10.1007/s12070-023-04043-2","DOIUrl":"10.1007/s12070-023-04043-2","url":null,"abstract":"<p><p>Retropharyngeal abscess (RPA) is a rare, potentially fatal condition found more frequently in young children usually who were having a history of Upper respiratory infection. RPA is an acute suppurative infection of the retropharyngeal space. In view of scarce literature availability and atypical presentation in infants, it poses a definitive diagnostic dilemma to the clinicians. Here, we are reporting a three-month-old male infant presented with feeding difficulty, obstructive sleep apnea and intermittent inspiratory stridor. Child was managed in a pediatric ICU with a multidisciplinary approach which involved pediatrician, otorhinolaryngologist pediatric anesthesiologist, microbiologist, and radiologist. With the recent advances, early radio imaging have a vital role in diagnosing the condition and also helps in planning of surgery. Prompt diagnosis and surgical management with appropriate antimicrobial therapy for this condition is imperative to prevent complications such as airway obstruction and mediastinitis. Timely surgical intervention, preferably intraoral transpharyngeal approach, to drain the abscess is recommended.</p>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"137 1","pages":"4066-4070"},"PeriodicalIF":1.4,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10646015/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74899031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The C2H4O isomers in the oxidation of ethylene","authors":"Nathan A. Seifert ,&nbsp;Branko Ruscic ,&nbsp;Raghu Sivaramakrishnan ,&nbsp;Kirill Prozument","doi":"10.1016/j.jms.2023.111847","DOIUrl":"https://doi.org/10.1016/j.jms.2023.111847","url":null,"abstract":"<div><p>A combined rotational spectroscopy, thermochemistry, and kinetic modeling study explores the mechanism of acetaldehyde (ethanal), vinyl alcohol (ethenol), and ethylene oxide (oxirane) formation in the oxidation of ethylene (ethene). Multiplexed quantitative detection of oxidation intermediates and products exiting a SiO₂/SiC microreactor at 1700 K is demonstrated with the BrightSpec W-band chirped-pulse Fourier transform millimeter-wave spectrometer. The broadband rotational spectrum contains transitions of formaldehyde (CH₂O), methoxy (CH₃O), methanol (CH₃OH), ketene (CH₂CO), acetaldehyde (CH₃CHO), <em>syn</em>-vinyl alcohol (<em>syn</em>-CH₂CHOH), <em>anti</em>-vinyl alcohol (<em>anti</em>-CH₂CHOH), oxirane (<em>c</em>-CH₂OCH₂), propyne (CH₃CCH), and <em>syn</em>-propanal (<em>syn</em>-CH₃CH₂CHO). We focus on the three C₂H₄O species and deduce their concentration ratio [CH₃CHO]:[CH₂CHOH]:[<em>c</em>-CH₂OCH₂] = 1:0.7(2):0.06(2) by comparing the observed line intensities to those simulated with the PGOPHER software. Detailed thermochemistry of the C₂H₄O isomers and conformers is provided by Active Thermochemical Tables. The observed excess concentrations of vinyl alcohol and oxirane relative to the more stable acetaldehyde compared to the equilibrium ratio at 1700 K (1:0.087:0.000024), point to direct chemical pathways to these higher energy isomers. The mechanism for the formation of the three C₂H₄O isomers is analyzed using a 0-D homogenous reactor kinetics simulation for ethylene oxidation. The ratios of the C₂H₄O isomers concentrations predicted by the kinetic model are compared to the experimental values.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"398 ","pages":"Article 111847"},"PeriodicalIF":1.4,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92100879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}