Journal of Molecular Spectroscopy最新文献

{"title":"Microwave measurements, calculations, and analysis for the gas phase ammonia-formic acid dimer","authors":"Kristen K. Roehling,&nbsp;Jack L. Nichols,&nbsp;Adam M. Daly,&nbsp;Stephen G. Kukolich","doi":"10.1016/j.jms.2023.111772","DOIUrl":"10.1016/j.jms.2023.111772","url":null,"abstract":"<div><p>The gas-phase doubly hydrogen-bonded formic acid-ammonia complex was obtained by heating a sample of ammonium formate in neon. High-level DFT and MP2 calculations with various basis sets were performed and barriers for proton tunneling and internal rotation were determined. The microwave spectrum was measured in the 7–16 GHz frequency range using a Flygare-Balle type pulsed beam Fourier transform microwave (FTMW) spectrometer. Double resonance transitions were observed near 20 GHz. Rotational transitions were measured and fitted for two vibrational states to obtain the rotational constants and quadrupole coupling constants. The rotational constants were determined to have the following values: A = 12017.0(2), B = 4337.331(2), and C = 3227.279(2) for the 0⁺ state and A = 12017.0, B = 4302.02(1), and C = 3238.161(1) for the 0⁻ state and have been fit to 16 transitions and 9 transitions respectively. Each state was fit to a rigid model showing quadrupole splitting and compared with computations.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42229231","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 rotationally-resolved infrared spectrum of CD379Br and CD381Br between 900 and 1400 cm−1","authors":"T. Masiello ,&nbsp;J.W. Vant ,&nbsp;C.S. Brauer ,&nbsp;T.A. Blake","doi":"10.1016/j.jms.2023.111760","DOIUrl":"https://doi.org/10.1016/j.jms.2023.111760","url":null,"abstract":"<div><p>The infrared spectrum of CD₃⁷⁹Br and CD₃⁸¹Br between 900 cm⁻¹ and 1400 cm⁻¹ has been analyzed at high resolution. In this region, two fundamental vibrational states, <em>v</em>₂ = 1 and <em>v</em>₅ = 1, an overtone state, <em>v</em>₃ = 2, and a combination state, <em>v</em>₃ = <em>v</em>₆ = 1, have been analyzed for both isotopologues. As found in other halomethane molecules, strong Coriolis resonances couple the <em>v</em>₂ = 1 state to the <em>v</em>₅ = 1 state, and similar resonances were also used to describe the coupling found between the <em>v</em>₅ = 1 state to the <em>v</em>₃ = 2 state. A new determination of the <em>K</em>-dependent constant <em>A</em>₀ was performed for each isotopologue through the use of perturbation-allowed transitions. The values for <em>A</em>₀ determined from the analysis are 2.6001898(26) and 2.6001905(27) for CD₃⁷⁹Br and CD₃⁸¹Br, respectively. Density functional theory calculations were performed to examine the efficacy of high-level theoretical calculations to accurately predict spectroscopic constants. The density functional theory calculations had variable success with the largest errors associated with the prediction of the Δ<em>B</em> rotational constants of the interacting states.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49758680","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":"Erratum to “HCOOH high-resolution spectroscopy in the 9.18μ","authors":"L. Hilico, F. Bielsa, Anne Amy Klein","doi":"10.1016/j.jms.2023.111773","DOIUrl":"https://doi.org/10.1016/j.jms.2023.111773","url":null,"abstract":"","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45283215","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":"Erratum to “HCOOH high-resolution spectroscopy in the 9.18μm region” [J. Mol. Spectrosc. 247 (1) (2007) 41–46]","authors":"Laurent Hilico ,&nbsp;Franck Bielsa ,&nbsp;Anne Amy Klein","doi":"10.1016/j.jms.2023.111773","DOIUrl":"https://doi.org/10.1016/j.jms.2023.111773","url":null,"abstract":"<div><p>Absolute frequency measurement of HCCOH lines in coincidence with 9R(42) CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> laser line published in Bielsa et al. (2008) are corrected by 930 Hz.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49758629","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":"Measurements of perfluoro-n-heptane and perfluoro-n-octane absorption cross-sections from 300 to 350 K","authors":"Muhammad Osama Ishtiak ,&nbsp;Orfeo Colebatch ,&nbsp;Karine Le Bris ,&nbsp;Paul J. Godin ,&nbsp;Kimberly Strong","doi":"10.1016/j.jms.2023.111747","DOIUrl":"10.1016/j.jms.2023.111747","url":null,"abstract":"<div><p>Perfluoroalkanes are fully fluorinated greenhouse gases. These compounds are chemically inert due to their C–F bonds and therefore have atmospheric lifetimes of thousands of years. Although regulated under the Kyoto Protocol, atmospheric concentrations of perfluoroalkanes have continued to increase since 1997. To quantify the climate impact of perfluoro-n-heptane and perfluoro-n-octane, spectral data are required to calculate climate metrics such as the radiative efficiency and global warming potential. Experimental measurements are scarce for these compounds and are only available at 296 and 297 K. In this work, a set of absorption cross-sections is provided in the range 515–1500 cm⁻¹ at 0.1 cm⁻¹ resolution for nine temperatures between 300 and 350 K. There is general agreement between literature values and the absorption cross-sections and climate metrics measured in this work. These quantities do not show significant temperature dependence. The temperature averaged radiative efficiency is 0.50 ± 0.06 and 0.54 ± 0.07 Wm⁻²ppbv⁻¹ for n–C₇F₁₆ and n–C₈F₁₈, respectively. The temperature averaged 100-year global warming potential is 8738 ± 1149 for n–C₇F₁₆ and 8392 ± 1103 for n–C₈F₁₈.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49663570","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":"Rotational spectra of singly substituted rare isotopologues of two conformers of 3,3,3-trifluoropropanol","authors":"Alex N. Mort,&nbsp;Yunjie Xu","doi":"10.1016/j.jms.2023.111745","DOIUrl":"10.1016/j.jms.2023.111745","url":null,"abstract":"<div><p>The conformational distribution and the associated conformational conversion paths of 3,3,3-trifluoropropanol (TFP) were explored experimentally and theoretically using jet-cooled chirped pulse and cavity Fourier transform microwave spectroscopy in tandem with quantum chemical calculations. Rotational spectra of two TFP conformers, as well as their singly substituted ¹³C, ¹⁸O, and OD isotopologues, were measured and analyzed. The semi-experimental equilibrium rotational constants of the two conformers were also extracted for all isotopologues using the anharmonic calculations and used to obtain the semi-experimental equilibrium geometries.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42541421","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 0-0, 1-0, and 2-0 Bands of the [18.09]4 (5Δ4) -X4 (5Δ4) and [18.46]3 (5Δ3) – X3 (5Δ3) transitions of ruthenium monoxide (RuO)","authors":"G.M. Chenard ,&nbsp;A.G. Adam ,&nbsp;H. Zarringhalam ,&nbsp;D.W. Tokaryk ,&nbsp;C. Linton","doi":"10.1016/j.jms.2023.111742","DOIUrl":"10.1016/j.jms.2023.111742","url":null,"abstract":"<div><p><span>Laser Induced Fluorescence<span> (LIF) has been used to study the spectroscopy of ruthenium<span> monoxide (RuO) in the UNB laser-ablation molecular-jet apparatus. High-resolution spectra of the 0–0, 1–0 and 2–0 bands of the [18.09]4 – X4 and [18.46]3 – X3 transitions have been obtained with a linewidth (FWHM) of ∼100 MHz. Rotational structure of six individual isotopologues </span></span></span>⁹⁶RuO, ⁹⁹RuO, ¹⁰⁰RuO, ¹⁰¹RuO, ¹⁰²RuO and ¹⁰⁴<span>RuO was well resolved and used to examine the rotational and vibrational isotope effects<span>. In addition, hyperfine structure due to the nuclear spin (</span></span><em>I</em> = 5/2) of ⁹⁹Ru and ¹⁰¹<span>Ru has been resolved and used as an aid in establishing the electron configurations of the electronic states. The relative hyperfine widths in the </span><em>Ω</em> = 4 and 3 states are shown to be consistent with their assignment as components of ⁵Δ states.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41732948","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":"AI-3000K Infrared line list for hot CO2","authors":"Xinchuan Huang (黄新川) ,&nbsp;Richard S. Freedman ,&nbsp;Sergey Tashkun ,&nbsp;David W. Schwenke ,&nbsp;Timothy J. Lee","doi":"10.1016/j.jms.2023.111748","DOIUrl":"10.1016/j.jms.2023.111748","url":null,"abstract":"<div><p>AI-3000K is a semi-empirical IR line list constructed for hot CO₂ spectra analysis and simulation up to 3000 – 4000 K. Compared to previously published Ames-1000K and UCL-4000, it represents a major upgrade, utilizing a new algorithm for optimization and including the latest improvements in potential energy surface (PES), dipole moment surface (DMS), and room temperature IR line list (Ames-2021 296K). To maximize the success of introducing experimental based accurate line positions, a new PES (X01d) was refined with respect to &gt;800 selected CDSD2019 [Tashkun et al. JQSRT (2019) <strong>228</strong>, 124] energy levels in the range of 0 – 24,000 cm⁻¹, with σ_rms = 0.5 – 0.7 cm⁻¹. Most differences between the X01d PES based levels and CDSD2019 energies are within ± 2 cm⁻¹. A new DMS is fitted from extrapolated CCSD(T)/aug-cc-pV(T,Q,5)Z dipole calculations, with σ_rms = 5.1 × 10⁻⁶ au for 11,155 geometries up to 40,000 cm⁻¹, denoted Ames-2021–40K. Compared to the best available Ames-2021 DMS and room temperature IR line list [Huang et al J. Phys. Chem. A (2022) <strong>126</strong>, 5940], the relative intensity differences are expected to be ∼ 1 ‰. The line position accuracy of ''X01d + Ames-2021–40K'' IR line list is significantly improved by adopting CDSD2019 energy levels up to 24,000 cm⁻¹ (<em>J</em> ≤ 150). The Einstein <em>A</em>₂₁ coefficients for <em>E</em>' &lt; 15,000 cm⁻¹ transitions are replaced by more accurate values from the Ames-2021 296K IR line list. In short, the AI-3000K is the X01d PES and Ames-2021–40K DMS based line list enhanced with the <em>A</em>₂₁ of Ames-2021 296K line list and CDSD energy levels. It provides continuous coverage from 0 to 20,000 cm⁻¹ for the four most abundant isotopologues: ¹²C¹⁶O₂ (6<!--> <!-->2<!--> <!-->6), ¹³C¹⁶O₂ (6<!--> <!-->3<!--> <!-->6), ¹⁶O¹²C¹⁸O (6<!--> <!-->2<!--> <!-->8), and ¹⁶O¹²C¹⁷O (6<!--> <!-->2<!--> <!-->7). The impacts of isotopologue and <em>E</em>'/<em>E</em>'' cutoffs have been examined. Intensity convergence (not accuracy) of AI-3000K line list is quantitatively estimated in 1 cm⁻¹ bins. It is better than 99% in the whole range of 0 – 20,000 (or 10,000) cm⁻¹ at 1000 K (or 2000 K), or better than 90% in the whole range of 0 – 15,000 (or 9000) cm⁻¹ at 2000 K (or 3000 K), respectively. Convergence beyond 3000 K will require a new PES and DMS for <em>E</em>' &gt; 40,000 cm⁻¹. The AI-3000K and HITEMP based IR simulations are compared to high resolution shock tube experiments for CO₂-Ar mixture up to 2000 K. With line position accuracy comparable to that of HITEMP, AI-3000K IR line list yields better agreements at more frequencies. Potential sources of d","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44417636","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":"High-resolution rovibrational spectroscopy of trans-formic acid in the v1 OH stretching fundamental: Dark state coupling and evidence for charge delocalization dynamics","authors":"Ya-Chu Chan ,&nbsp;David J. Nesbitt","doi":"10.1016/j.jms.2023.111743","DOIUrl":"10.1016/j.jms.2023.111743","url":null,"abstract":"<div><p><span>High-resolution infrared (IR) reduced-Doppler absorption spectra of jet-cooled gas phase </span><em>trans</em>-formic acid in the <em>v</em>₁ OH stretching fundamental region are reported for the first time, obtained by supersonically expanding <em>trans-</em>formic acid/Ar mixtures through a slit jet nozzle source and rotationally cooling to T_rot<span> ≈ 10.9(5) K, with absorption signals recorded by high-resolution difference-frequency IR absorption spectroscopy. Two </span><em>a</em>/<em>b</em>-type rovibrational bands of comparable intensity, one ∼10-fold weaker <em>b</em>-type band, and one ∼6-fold weaker <em>a</em>-type band are observed, with vibrational band origins at 3570.493(5), 3566.793(5), 3560.032(9), and 3534.6869(2) cm⁻¹, respectively. Based on previous Raman jet spectroscopic work by Nejad and Sibert [A. Nejad, E.L. Sibert III, The Raman jet spectrum of <em>trans</em>-formic acid and its deuterated isotopologs: Combining theory and experiment to extend the vibrational database, J. Chem. Phys. 154(6) (2021) 064301.], these four rovibrational bands have been assigned to <em>v</em>₁, (<em>v</em>₂ + <em>v</em>₇), (<em>v</em>₆ + 2<em>v</em>₇ + 2<em>v</em>₉), and 2<em>v</em>₃, respectively. Specifically, two of the three upper dark states (2¹7¹ (<em>a</em>′) and 6¹7²9² (<em>a</em>′)) are close enough to the “bright” 1¹ (<em>a</em>′) state to facilitate strong anharmonic resonance interactions, which results in intensity mixing into the two zero-order bands that would otherwise be “dark”. Furthermore, our high-resolution spectral analysis reveals that there are local rotational crossings between these zero-order 1¹ and 2¹7¹ states resulting in extra lines (i.e., some upper levels in the nominally <em>v</em>₁ band have majority zero-order 2¹7¹ state character). This motivates development of a 3 coupled state (1¹, 2¹7¹, and 6¹7²9²) picture to aid in the spectral analysis, which is able to match all 3 observed band origins and relative band intensities, as well as indicate the necessity of multistate (&gt; 2) coupling. Though limited by range of <em>J</em> and <em>K</em>_a levels (<em>J'</em> ≤ 9 and <em>K</em>_<em>a</em><em>'</em><span>  ≤ 3) populated at supersonic<span> jet temperatures, this work offers first precision spectroscopic analysis of </span></span><em>trans</em>-formic acid in the <em>v</em>₁<span><span> OH stretch region, which should aid in assignment of the more complete yet highly congested room temperature </span>FTIR spectra [D. Hurtmans, F. Herregodts, M. Herman, J. Liévin, A. Campargue, A. Garnache, A. Kachanov, Spectroscopic and ab initio investigation of the ν</span><s","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44563545","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":"FTIR synchrotron spectroscopy of lower modes of methyl-D3 mercaptan (CD3SH)","authors":"C.W. Beaman ,&nbsp;R.M. Lees ,&nbsp;Li-Hong Xu ,&nbsp;B.E. Billinghurst","doi":"10.1016/j.jms.2023.111739","DOIUrl":"10.1016/j.jms.2023.111739","url":null,"abstract":"<div><p>The infrared Fourier transform spectrum of the lower vibrational modes of the CD₃SH isotopologue of methyl mercaptan has been recorded using synchrotron radiation at the FIR beamline of the Canadian Light Source. Torsion-rotation structure has been analyzed for a strong parallel band centred at 644 cm⁻¹ and a weaker perpendicular band centred at 727 cm⁻¹, identified respectively with a mixed {in-plane-CD₃-rocking/CSH-bending} mode and the out-of-plane CD₃ rock. The torsional energies for the latter mode follow well-behaved curves, inverted with respect to the ground state, but those for the former do not display a systematic pattern. Surprisingly, no clear evidence was seen for the C-S stretching fundamental band, in contrast to CH₃SH and the analogous CD₃OH and CH₃OH methanol species for which the corresponding C-S or C-O stretching bands are major features of the spectrum. This mystery prompted an <em>ab initio</em> calculation to compare the CD₃SH and CH₃SH vibrational frequencies and transition moments. A mode lying in the expected position was indeed predicted for CD₃SH but with almost vanishing intensity. The calculated reduced mass and effective force constant for this mode corresponded closely to those for the C-S stretch of normal CH₃SH, indicating that an anticipated strong C-S stretching band is in fact almost completely extinguished for CD₃SH.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48920396","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}