Journal of Molecular Spectroscopy最新文献

{"title":"Ammonia – Formic acid complex: internal rotation analysis, calculations, and new microwave measurements","authors":"Kristen K. Roehling,&nbsp;Rhett P. Hill,&nbsp;Adam M. Daly,&nbsp;Stephen G. Kukolich","doi":"10.1016/j.jms.2024.111884","DOIUrl":"10.1016/j.jms.2024.111884","url":null,"abstract":"<div><p>New analysis and spectra are reported for the gas-phase ammonia-formic acid complex. Calculations to determine the theoretical barrier to internal rotation were conducted and led to the new internal rotation analysis of the dimer. Using the new analysis and calculations, 12 new lines were measured and assigned and included in the present analysis. This is the first internal rotation analysis for this complex. The measurements were made in the 7–22 GHz range using two Flygare-Balle type pulsed beam Fourier transform microwave (FTMW) spectrometers. The complex was analyzed as a hindered rotor and 20 A and 16 E state transitions were fit with the XIAM5 program. The rotational constants were determined to have the following values: A = 11970.19(9) MHz, B = 4331.479(4) MHz, and C = 3227.144(4) MHz. Rotational constants, quadrupole coupling constants, and internal rotor parameters were fit to the spectrum. Double resonance was used to verify line assignments and access higher frequencies. The barrier to internal rotation was found to be 195.18(7) cm⁻¹. High level calculations are in good agreement with experimental values. The calculated V₃ barrier values range from 168.3 to 212.8 cm⁻¹.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"400 ","pages":"Article 111884"},"PeriodicalIF":1.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139496437","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":"<div><p>A total of 11 fundamental and 3 overtone bands of the formaldoxime isotopologue ¹³CD₂NOH were identified using its Fourier transform infrared (FTIR) spectra which were recorded with a low resolution (0.50 cm⁻¹) in the 500–4000 cm⁻¹ region, and high resolution (0.00096 cm⁻¹) in the 280–500 cm⁻¹ region. Their relative infrared (IR) band intensities were also measured. Furthermore, a rovibrational analysis of the IR transitions of the <span><math><mrow><msub><mi>ν</mi><mn>12</mn></msub></mrow></math></span> band of ¹³CD₂<span>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 </span><em>C</em>-type <span><math><mrow><msub><mi>ν</mi><mn>12</mn></msub></mrow></math></span> band were assigned and fitted using the Watson's <em>A</em>-reduced Hamiltonian in the <em>I^r</em> representation to derive its band center and the <span><math><mrow><msub><mi>v</mi><mn>12</mn></msub></mrow></math></span><span> = 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</span>⁻¹. The band center of the <span><math><mrow><msub><mi>ν</mi><mn>12</mn></msub></mrow></math></span> band of ¹³CD₂NOH were found to be 391.054446(36) cm⁻¹. 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 <span><math><mrow><msub><mi>ν</mi><mn>12</mn></msub></mrow></math></span> band of ¹³CD₂NOH of this work. The rms deviation of the GSCD fit was 0.00040 cm⁻¹<span>. Additionally, all 3 rotational constants and 5 quartic centrifugal distortion terms of the ground state and 3 rotational constants of the </span><span><math><mrow><msub><mi>v</mi><mn>12</mn></msub></mrow></math></span> = 1 state of ¹³CD₂<span>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 </span>¹³CD₂NOH for both ground and <span><math><mrow><msub><mi>v</mi><mn>12</mn></msub></mrow></math></span> = 1 states. The vibrational anharmonic frequencies of the 12 fundamental bands of ¹³CD₂NOH in the 280–4000 cm⁻¹ 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 <span><math><mrow><msub><mi>ν</mi><mn>12</mn></msub></mrow></math>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"400 ","pages":"Article 111885"},"PeriodicalIF":1.4,"publicationDate":"2024-01-17","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":"Coulombic or electrostatic: Determination of the effects of substitution on the structures of 2-, 3-, and 4-picolylamine using Fourier transform microwave spectroscopy","authors":"Kaylee X. Shook,&nbsp;Lindsey M. McDivitt,&nbsp;Caleb D. Shiery,&nbsp;Josiah R. Bailey,&nbsp;Timothy J. McMahon,&nbsp;Robert A. Grimminger,&nbsp;Ryan G. Bird","doi":"10.1016/j.jms.2024.111874","DOIUrl":"10.1016/j.jms.2024.111874","url":null,"abstract":"<div><p>In this study, the microwave spectra of 2-, 3-, and 4-picolyamine were recorded in a pulsed supersonic jet. With the aid of Natural Bond Orbital analysis, NCIplot, and Multiwfn, the structural effects of substitution were explored and then quantified by comparing semi-experimental geometries. The conformational landscape of each molecule is dominated by Van der Waals interactions between the amino group and the pyridine ring. Spectra of ²H, ¹³C, and ¹⁵N were also collected and analyzed.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"400 ","pages":"Article 111874"},"PeriodicalIF":1.4,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139396291","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":"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":"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":"2023-12-05","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":"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":"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":"2023-11-29","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":"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":"2023-11-22","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}