{"title":"Rotational spectra of ten new fluoroethylene/CO2 clusters, (C2H3F)x(CO2)y: Application of data-centered methods to the assignment of spectra in complex mixtures","authors":"","doi":"10.1016/j.jms.2024.111938","DOIUrl":"10.1016/j.jms.2024.111938","url":null,"abstract":"<div><p>Chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy has been used to measure the spectra of ten previously unobserved fluoroethylene (FE)/CO<sub>2</sub> clusters, (FE)<sub>x</sub>(CO<sub>2</sub>)<sub>y</sub>, with x from 1 to 4 and y from 0 to 4. Multiple spectra were recorded with varying concentrations of CO<sub>2</sub> in the sample, and at least 400,000 free induction decays averaged per data set. This allowed implementation of data-centered approaches, using intensity variation, to identify subsets of transitions belonging to the same cluster species or those of similar composition, simplifying the assignment process for the complex mixture of clusters present. All spectra were fitted to Watson <em>A</em>-reduction Hamiltonians, including quartic distortion constants, with very few species requiring higher order distortion constants for satisfactory fits to be obtained. Computational data at MP2/6-311++G(2d,2p) and <em>ω</em>B97X-D/6-31+G(d,p) levels suggested FE:CO<sub>2</sub> ratios and likely structural arrangements of each cluster based on comparisons with experimental rotational constants.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0022285224000651/pdfft?md5=2176ca31fb02fa6cd55c89dd81def90e&pid=1-s2.0-S0022285224000651-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142099086","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":"Symmetry properties, tunneling splittings of some vibrational energy levels and torsional IR spectra of the trans – and cis – conformers of hydroquinone molecule","authors":"","doi":"10.1016/j.jms.2024.111937","DOIUrl":"10.1016/j.jms.2024.111937","url":null,"abstract":"<div><p>Torsional vibrational states of trans − and cis − conformers belonging to point symmetry groups C<sub>2H</sub> and C<sub>2V</sub>, respectively, of hydroquinone molecules are classified according to the irreducible representations of the molecular symmetry group D<sub>2H</sub>(M). A correspondence has been established between the symmetry elements of the D<sub>2H</sub>(M) group and the symmetry elements on the torsional coordinate plane for two-dimensional surfaces of potential energy, wave functions, kinetic coefficients and dipole moment projections. A correspondence has been established between the symmetry species of the point symmetry groups C<sub>2H</sub>, C<sub>2V</sub> and the symmetry species of the molecular symmetry group D<sub>2H</sub>(M). Conformational states, barriers to internal rotation and the above-mentioned characteristics of the hydroquinone molecule were calculated at the MP2/Aug-cc-pVDZ, MP2/Aug-cc-pVQZ, MP2/Aug-cc-pVTZ, MP2/CBS(aD,aT,aQ), and CCSD(T)/dAug-cc-pVDZ levels of theory. The calculated data sets were approximated using symmetry-adapted sets of basis functions. Using a numerical solution of the vibrational Schrödinger equation of restricted dimensionality, the energies and wave functions of 50 stationary torsional states of the hydroquinone molecule were determined for the first time. The values of tunneling splittings of the ground vibrational and a number of excited torsional states of trans − and cis − conformers were determined. In particular, when calculating at the MP2/CBS(aD,aT,aQ) level of theory, the values of tunneling splittings of the ground vibrational states of trans − and cis − conformers turned were 1.32*10<sup>-6</sup> and 1.62*10<sup>-6</sup> cm<sup>−1</sup>, which is consistent with the experimentally established upper limit for this value in the cis − conformer by authors of [W. Caminati, S. Melandri, L. B. Favero, J.Chem.Phys., 100 (1994) 8569 – 8572] (0.2 MHz or 6.67*10<sup>-6</sup> cm<sup>−1</sup>). The calculations of the matrix elements of the dipole moment operator and the partition function made it possible to simulate the torsional IR spectra of the molecule’s conformers at different temperatures. The frequencies of fundamental torsional vibrations in the trans – (267.1 and 269.0 cm<sup>−1</sup>) and cis – (269.5 and 270.9 cm<sup>−1</sup>) conformers, calculated at the MP2/CBS(aD,aT,aQ) level of theory, are in good agreement with the experimental value of frequency of this vibration (266 cm<sup>−1</sup>), established in [W.G. Fateley, G.L. Carlson, F.F. Bentley, J.Phys.Chem., 79 (1975) 199–204.].</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142002451","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":"Molecular structure analysis of xanthine alkaloids using terahertz spectroscopy","authors":"","doi":"10.1016/j.jms.2024.111936","DOIUrl":"10.1016/j.jms.2024.111936","url":null,"abstract":"<div><p>Caffeine, theophylline and theobromine are representative xanthine alkaloids, commonly used as stimulants due to their effects on the central nervous system. Despite their similar molecular structures, they have different pharmacological effects, necessitating a rapid and accurate identification method. In this study, terahertz time-domain spectroscopy (THz-TDS) was used to measure the absorption spectra of these three xanthine alkaloids within the range of 2.0–17.0 THz. The characteristic absorption peaks were visualized and analyzed basing on the quantum chemical calculations using Hartree-Fock (HF), Møller–Plesset perturbation theory (MP2) and density functional theory (DFT). Caffeine exhibited unique absorption peaks at 4.24, 5.00, and 11.13 THz. Theophylline showed characteristic peaks at 9.25, 12.20, and 15.09 THz. While theobromine exhibited characteristic peaks at 4.45, 7.68, and 11.21 THz. The results demonstrate that combining THz-TDS with DFT calculation can non-destructively, efficiently, and accurately identify these xanthine alkaloids, and providing valuable information for further understanding their pharmacological functions.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142012208","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":"Theoretical investigation of the electronic structure of the Rhodium Halides molecules RhF and RhCl with dipole moment calculation","authors":"","doi":"10.1016/j.jms.2024.111929","DOIUrl":"10.1016/j.jms.2024.111929","url":null,"abstract":"<div><p>The current study involves an <em>ab</em> initio exploration of the ground and low-lying excited electronic states of the rhodium halide molecules RhF and RhCl using the complete active space self-consistent field (CASSCF) with multireference configuration interaction (MRCI+Q) method including single and double excitations and with Davidson corrections. We investigated the potential energy curves, the transition and permanent electric dipole moments, the electronic energy relative to the ground state <em>T<sub>e</sub></em>, the harmonic frequency <em>ω<sub>e</sub></em>, the internuclear distance <em>R<sub>e</sub></em>, and the rotational constant <em>B<sub>e</sub></em> corresponding to each of the bounded states. Our findings demonstrate good agreement with the available experimental data. Notably, this work represents the inaugural theoretical investigation of the excited states of RhF and RhCl molecules, identifying the ground state of both to be X<sup>3</sup>Π, as observed in the sole two experimental investigations.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141777157","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":"westerfit: A new program for spin–torsion–rotation spectra","authors":"","doi":"10.1016/j.jms.2024.111928","DOIUrl":"10.1016/j.jms.2024.111928","url":null,"abstract":"<div><p>A new program, <span>westerfit</span>, has been developed to treat <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> molecules with internal rotation and spin angular momentum. It implements a single diagonalization Rho Axis Method approach for the torsion–rotation alongside a complete treatment of nuclear quadrupole interaction and spin–rotation coupling. Unlike other programs designed for internal rotation with spin effects, <span>westerfit</span> includes matrix elements off-diagonal in the rotational angular momentum quantum number, <span><math><mi>N</mi></math></span>, rather than the perturbative treatment of the spin–rotation and quadrupole interactions. This full combined approach allows fitting of all symmetrically allowed terms in both the spin–rotation and the quadrupole tensors as well as inclusion of higher order terms coupling the large amplitude motion to the spin angular momentum. The program was benchmarked against other published programs to test molecular cases of torsion–rotation, spin–rotation, and spin–torsion-rotation. All three tests produced a lower RMS. <span>westerfit</span> paves a way forward for complete treatment of spin–torsion–rotation problems regardless of barrier height or quadrupole moment.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141850717","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}
Nathan Love, Kenneth J. Koziol, Kaitlyn Belmont, Kenneth R. Leopold
{"title":"Microwave spectra of two carboxylic acid anhydrides: Acetic anhydride and acetic difluoroacetic anhydride","authors":"Nathan Love, Kenneth J. Koziol, Kaitlyn Belmont, Kenneth R. Leopold","doi":"10.1016/j.jms.2024.111926","DOIUrl":"10.1016/j.jms.2024.111926","url":null,"abstract":"<div><p>Microwave spectra of acetic anhydride, D6-acetic anhydride, and acetic difluoroacetic anhydride have been observed in a supersonic jet. In conjunction with accompanying DFT and MP2 calculations, these systems are shown to adopt a nonplanar configuration in which the C=O groups point in approximately orthogonal directions. Methyl group internal rotation was fully analyzed for both species. The observed conformation of these systems appears to result from an interaction between a CH<sub>3</sub> hydrogen (in acetic anhydride) or the CF<sub>2</sub>H hydrogen (in acetic difluoroacetic anhydride) with the carbonyl group to which it is not directly bound, forming a six-membered ring. The fitted rotational constants for both systems are in reasonably good agreement with calculated values, but for acetic anhydride, the agreement is somewhat worse than that previously observed for a series of <em>syn</em> anhydrides. The calculations indicate a pronounced flexing of the heavy atom frame as the CH<sub>3</sub> group in the six-membered ring undergoes internal rotation, and this likely influences the level of agreement between the theoretical and vibrationally averaged experimental constants. The other CH<sub>3</sub> group does not interact with a carbonyl oxygen because of its orientation in the molecule, and its internal rotation does not induce similar changes in the molecular frame. In the acetic difluoroacetic anhydride, it is the CF<sub>2</sub>H hydrogen that interacts with its remote carbonyl oxygen, leaving the internally rotating CH<sub>3</sub> group unaffected by participation in a six-membered ring and giving rise to much smaller deviations in the rotational constants as it moves along its internal rotation coordinate. Correspondingly better agreement between experimental and theoretical spectroscopic constants is obtained.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141411723","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}
Aaron J. Reynolds , Diego E. Rodriguez , Wei Lin , Kenneth R. Leopold
{"title":"Microwave spectroscopy and large amplitude motion of chlorosulfonic acid (ClSO2OH)","authors":"Aaron J. Reynolds , Diego E. Rodriguez , Wei Lin , Kenneth R. Leopold","doi":"10.1016/j.jms.2024.111927","DOIUrl":"https://doi.org/10.1016/j.jms.2024.111927","url":null,"abstract":"<div><p>The high-resolution rotational spectrum of chlorosulfonic acid (ClSO<sub>2</sub>OH) has been studied using both broadband and cavity-based Fourier transform microwave spectrometers over the frequency range of 5–18 GHz. <em>a</em>-, <em>b</em>-, and <em>c</em>-type transitions have been recorded for both the <sup>35</sup>Cl and <sup>37</sup>Cl isotopologues. The observation of <em>c</em>-type lines establishes that the molecule lacks a plane of symmetry and suggests that the OH group can undergo large amplitude motion between equivalent structures. Interconversion between these structures can be achieved via internal rotation through two inequivalent barriers occurring at Cl-S-O-H torsional angles of 0 or 180<!--> <!-->degrees. As in previous work on triflic and methanesulfonic acids, two states are observed and are treated as tunneling states which are presumed to arise primarily due to motion through the lower of the two barriers. The <em>a</em>- and <em>c</em>-type transitions occur within each of these states while the <em>b</em>-type transitions cross between them. Rotational, centrifugal distortion, and chlorine nuclear quadrupole coupling constants, as well as the energy difference between the two tunneling states and associated coupling constants, have been determined. The experimental tunneling energies, <em>ΔE</em>, for the <sup>35</sup>Cl and <sup>37</sup>Cl isotopologues are 52.6926(16) MHz and 52.6397(46) MHz, respectively. Quantum chemical calculations were carried out using MP2 and B3LYP density functional theory (DFT) methods with an aug-cc-pVTZ basis set. The rotational constants from the optimized structures were in good agreement with the experimental values. The lowest energy barrier for OH motion was calculated to be 2.63 kcal/mol at the B3LYP/aug-cc-pVTZ level. The effects of the large amplitude motion are similar to those recently reported for triflic acid (CF<sub>3</sub>SO<sub>2</sub>OH) and methanesulfonic acid (CH<sub>3</sub>SO<sub>2</sub>OH). However, while the tunneling splittings in chlorosulfonic and triflic acids are virtually identical, they differ significantly from that of methanesulfonic acid.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141486897","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}
M. Gochitashvili , R. Lomsadze , R.Ya. Kezerashvili , I. Noselidze , M. Schulz
{"title":"Radiative emissions from charge exchange processes in collisions of 0.7–10.0 keV He+ with N2 and O2 molecules","authors":"M. Gochitashvili , R. Lomsadze , R.Ya. Kezerashvili , I. Noselidze , M. Schulz","doi":"10.1016/j.jms.2024.111916","DOIUrl":"https://doi.org/10.1016/j.jms.2024.111916","url":null,"abstract":"<div><p>We present an experimental study of the dissociative excitation in the collision of helium ions with nitrogen and oxygen molecules for collision energy of <span><math><mrow><mn>0</mn><mo>.</mo><mn>7</mn><mtext>–</mtext><mn>10</mn><mo>.</mo><mn>0</mn></mrow></math></span> keV. Absolute emission cross sections are measured and reported for the most pronounced nitrogen and oxygen atomic and ionic lines in vacuum ultraviolet (<span><math><mrow><mn>80</mn><mtext>–</mtext><mn>130</mn><mspace></mspace><mi>nm</mi></mrow></math></span>) and visible (<span><math><mrow><mn>380</mn><mtext>–</mtext><mn>670</mn><mspace></mspace><mi>nm</mi></mrow></math></span>) spectral regions. Remarkable similarities of the processes realized in He<span><math><mrow><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup><mo>+</mo></mrow></math></span>N<sub>2</sub> and He<span><math><mrow><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup><mo>+</mo></mrow></math></span>O<sub>2</sub> collision systems are observed. We present polarization measurements for He<span><math><mrow><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup><mo>+</mo></mrow></math></span>N<sub>2</sub> collision system.</p><p>The emission of excited dissociative products was detected using an improved high-resolution optical spectroscopy method. This method incorporates the retarding potential method and a high resolution electrostatic energy analyzer to precisely measure the energy of incident particles and the energy of dispersion. The improvement in the optical sensitivity allows us to measure the cross section on the order of 10<sup>−19</sup> cm<sup>2</sup> or lower.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141291932","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 structure and rotationally resolved autodetachment spectrum of H15NO– and H14NO– near 3000 cm−1","authors":"Daniel C. Cowles , John W. Farley , J.L Hardwick","doi":"10.1016/j.jms.2024.111915","DOIUrl":"10.1016/j.jms.2024.111915","url":null,"abstract":"<div><p>The rotationally resolved vibrational autodetachment spectrum of the H<sup>15</sup>NO<sup>–</sup> anion has been observed in the region from 2932 to 3092 <span><math><msup><mrow><mi>cm</mi></mrow><mrow><mo>-</mo><mn>1</mn></mrow></msup></math></span>. <span><math><mrow><msub><mrow><msup><mrow><mspace></mspace></mrow><mi>r</mi></msup><mi>R</mi></mrow><mi>K</mi></msub><mfenced><mrow><mi>N</mi></mrow></mfenced></mrow></math></span> branches were observed for <span><math><mrow><mi>K</mi><mo>=</mo><mn>4</mn></mrow></math></span> through 8, and two <span><math><mrow><msub><mrow><msup><mrow><mspace></mspace></mrow><mi>r</mi></msup><mi>Q</mi></mrow><mi>K</mi></msub><mfenced><mrow><mi>N</mi></mrow></mfenced></mrow></math></span> branches with <span><math><mrow><mi>K</mi><mo>=</mo><mn>5</mn></mrow></math></span> and 6 were assigned. The <span><math><mrow><msub><mrow><msup><mrow><mspace></mspace></mrow><mi>r</mi></msup><mi>Q</mi></mrow><mn>5</mn></msub><mfenced><mrow><mi>N</mi></mrow></mfenced></mrow></math></span> branch of H<sup>14</sup>NO<sup>–</sup> has also been identified. The new observations have allowed a rotational analysis of H<sup>15</sup>NO<sup>–</sup> and have required a re-analysis of the previously observed spectrum of H<sup>14</sup>NO<sup>–</sup>. The spectra are consistent with a ground state (<span><math><msubsup><mi>r</mi><mrow><mi>m</mi></mrow><mfenced><mrow><mn>1</mn></mrow></mfenced></msubsup></math></span>) geometry of <span><math><mrow><msub><mi>r</mi><mrow><mi>NH</mi></mrow></msub><mo>=</mo><mn>1.099</mn><mi>Å</mi></mrow></math></span>, <span><math><mrow><msub><mi>r</mi><mrow><mi>NO</mi></mrow></msub><mo>=</mo><mn>1.330</mn><mi>Å</mi></mrow></math></span>, and <span><math><mrow><mi>∠</mi><mi>H</mi><mi>N</mi><mi>O</mi><mo>=</mo><msup><mrow><mn>105.5</mn></mrow><mo>°</mo></msup></mrow></math></span>, in good agreement with the results of Ellis and Ellison for the N<img>O bond length and comparing well with recent theoretical treatments of this anion. The band has been reassigned as the <span><math><mrow><mfenced><mrow><mrow><mn>0</mn><mo>,</mo><mn>2</mn></mrow><mo>,</mo><mn>0</mn></mrow></mfenced><mo>-</mo><mrow><mo>(</mo><mrow><mn>0</mn><mo>,</mo><mn>0</mn></mrow><mo>,</mo><mn>0</mn><mo>)</mo></mrow></mrow></math></span> band.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141139958","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":"Thermodynamic functions of germane isotopologues AGeH4 (A = 70, 72, 73, 74, 76) calculated from high-resolution IR spectra","authors":"I.A. Velmuzhova , M.A. Koshelev , A.P. Velmuzhov , O.N. Ulenikov , O.V. Gromova","doi":"10.1016/j.jms.2024.111914","DOIUrl":"10.1016/j.jms.2024.111914","url":null,"abstract":"<div><p>Standard thermodynamic functions of germane isotopologues <sup>70</sup>GeH<sub>4</sub>, <sup>72</sup>GeH<sub>4</sub>, <sup>73</sup>GeH<sub>4</sub>, <sup>74</sup>GeH<sub>4</sub>, and <sup>76</sup>GeH<sub>4</sub> are calculated in “harmonic oscillator – rigid rotator” and “anharmonic oscillator – oscillating non-rigid rotator” approximations and by the direct summation of the experimental energy values. To found the values of thermodynamic functions in the 200–700 K temperature range, approximation coefficients are determined by regression analysis. The isotope effect influence on the values of the standard isobaric heat capacity, entropy, enthalpy of heating, and the reduced isobaric-isothermal potential of germane is established. Limiting requirements for the accuracy of determining the spectral parameters for detecting the influence of the isotope effect on the thermodynamic functions and interatomic distances in the germane molecule are formulated.</p></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141053095","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}