Pub Date : 2025-01-01Epub Date: 2024-12-20DOI: 10.1016/j.jms.2024.111982
Manamu Kobayashi , Kaori Kobayashi , Brian J. Esselman , R.Claude Woods , Robert J. McMahon , Satoshi Yamamoto , Hiroyuki Ozeki
The rotational spectrum of dichloromethane (methylene chloride, CH2Cl2) was measured with near-continuous frequency coverage from 29 to 750 GHz with 50 kHz resolution, with additional transitions around 11 GHz with 20 kHz resolution. The rest frequencies of transitions for both the vibrational ground state and first fundamental ν4 are observed, measured, and least-squares fit. Transitions for both of these vibrational states are modeled with partial octic, distorted rotor A- and S-reduced Hamiltonians in the Ir representation with nuclear quadrupole coupling. Computed spectroscopic constants at the B3LYP/6–311+G(2d,p) level are compared to their corresponding experimental values. The partition function of dichloromethane is updated.
{"title":"The rotational spectroscopy of dichloromethane (CH235Cl2) in the ground state and ν4 vibrationally excited state from 11 to 750 GHz","authors":"Manamu Kobayashi , Kaori Kobayashi , Brian J. Esselman , R.Claude Woods , Robert J. McMahon , Satoshi Yamamoto , Hiroyuki Ozeki","doi":"10.1016/j.jms.2024.111982","DOIUrl":"10.1016/j.jms.2024.111982","url":null,"abstract":"<div><div>The rotational spectrum of dichloromethane (methylene chloride, CH<sub>2</sub>Cl<sub>2</sub>) was measured with near-continuous frequency coverage from 29 to 750 GHz with 50 kHz resolution, with additional transitions around 11 GHz with 20 kHz resolution. The rest frequencies of transitions for both the vibrational ground state and first fundamental ν<sub>4</sub> are observed, measured, and least-squares fit. Transitions for both of these vibrational states are modeled with partial octic, distorted rotor A- and S-reduced Hamiltonians in the I<em><sup>r</sup></em> representation with nuclear quadrupole coupling. Computed spectroscopic constants at the B3LYP/6–311+G(2d,p) level are compared to their corresponding experimental values. The partition function of dichloromethane is updated.</div></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"407 ","pages":"Article 111982"},"PeriodicalIF":1.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143171323","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}
Pub Date : 2025-01-01Epub Date: 2024-12-31DOI: 10.1016/j.jms.2024.111983
Joshua Heuvel-Horwitz , Eisen C. Gross , Trevor J. Sears
We describe a project designed to introduce senior undergraduate chemistry and physics majors to the use of more advanced laser spectroscopic techniques and the interpretation of spectroscopic line shapes. We present a spectrometer design comprising modular components that are controlled using a single Python program with a graphical user interface (GUI). Unlike commercial Fourier transform infrared spectrometers typically used in undergraduate laboratories, this instrument can measure much higher resolution (approximately 0.001 cm−1 compared to 0.5 cm−1) data, with significantly higher (10−4) fractional absorption sensitivity. The modular, opentable design allows for easy viewing of optical components and better understanding of the operation of the instrument. We demonstrate the functionality of the spectrometer by measuring the P(23) rotational-vibrational line of the combination band of acetylene at various pressures to extract a self-pressure broadening coefficient. An undergraduate laboratory assignment could also include estimating the Boltzmann constant from data for low pressure Doppler-broadened lines. An additional Python program with a GUI was built for user friendly least squares fitting of collected data. All Python codes developed are freely available on GitLab.
{"title":"Python control of a high-resolution near-infrared spectrometer for undergraduate use","authors":"Joshua Heuvel-Horwitz , Eisen C. Gross , Trevor J. Sears","doi":"10.1016/j.jms.2024.111983","DOIUrl":"10.1016/j.jms.2024.111983","url":null,"abstract":"<div><div>We describe a project designed to introduce senior undergraduate chemistry and physics majors to the use of more advanced laser spectroscopic techniques and the interpretation of spectroscopic line shapes. We present a spectrometer design comprising modular components that are controlled using a single Python program with a graphical user interface (GUI). Unlike commercial Fourier transform infrared spectrometers typically used in undergraduate laboratories, this instrument can measure much higher resolution (approximately 0.001 cm<sup>−1</sup> compared to 0.5 cm<sup>−1</sup>) data, with significantly higher (10<sup>−4</sup>) fractional absorption sensitivity. The modular, open<span><math><mo>−</mo></math></span>table design allows for easy viewing of optical components and better understanding of the operation of the instrument. We demonstrate the functionality of the spectrometer by measuring the P(23) rotational-vibrational line of the <span><math><mrow><msub><mrow><mi>ν</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>+</mo><msub><mrow><mi>ν</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math></span> combination band of acetylene at various pressures to extract a self-pressure broadening coefficient. An undergraduate laboratory assignment could also include estimating the Boltzmann constant from data for low pressure Doppler-broadened lines. An additional Python program with a GUI was built for user friendly least squares fitting of collected data. All Python codes developed are freely available on GitLab.</div></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"407 ","pages":"Article 111983"},"PeriodicalIF":1.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143171325","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}
Pub Date : 2025-01-01Epub Date: 2024-12-18DOI: 10.1016/j.jms.2024.111980
J.H. Westerfield , S.E. Worthington-Kirsch , Kyle N. Crabtree
{"title":"Corrigendum to “westerfit: A new program for spin–torsion–rotation spectra” [J. Mol. Spectrosc. 404 (2024) 111928]","authors":"J.H. Westerfield , S.E. Worthington-Kirsch , Kyle N. Crabtree","doi":"10.1016/j.jms.2024.111980","DOIUrl":"10.1016/j.jms.2024.111980","url":null,"abstract":"","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"407 ","pages":"Article 111980"},"PeriodicalIF":1.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143171327","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}
Pub Date : 2024-11-01Epub Date: 2024-10-11DOI: 10.1016/j.jms.2024.111952
Joshua E. Isert , Josie R. Glenn , S.A. Cooke , G.S. Grubbs II
Pure rotational transitions for HfS and ThS have been measured in highly excited vibrational states. For HfS, rotational transitions have been recorded in up to the 19th excited vibrational state, whereas for ThS measurements extend up to the 17th excited vibrational state. Pure rotational transitions have also been recorded for Th34S for the first time. In both cases isotopically invariant analyses have been performed and very accurate equilibrium bond lengths have been determined.
{"title":"Pure rotational spectroscopic measurements on the electronic ground states of Hafnium monosulfide and Thorium monosulfide in highly excited vibrational states","authors":"Joshua E. Isert , Josie R. Glenn , S.A. Cooke , G.S. Grubbs II","doi":"10.1016/j.jms.2024.111952","DOIUrl":"10.1016/j.jms.2024.111952","url":null,"abstract":"<div><div>Pure rotational transitions for HfS and ThS have been measured in highly excited vibrational states. For HfS, rotational transitions have been recorded in up to the 19th excited vibrational state, whereas for ThS measurements extend up to the 17th excited vibrational state. Pure rotational transitions have also been recorded for Th<sup>34</sup>S for the first time. In both cases isotopically invariant analyses have been performed and very accurate equilibrium bond lengths have been determined.</div></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"406 ","pages":"Article 111952"},"PeriodicalIF":1.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535261","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}
Pub Date : 2024-11-01Epub Date: 2024-10-11DOI: 10.1016/j.jms.2024.111953
Thomas Howard, Shannon E. Ganley, Sanjana Maheshwari, Leah G. Dodson
We describe an instrument that uses continuous-wave (CW) cavity-ringdown spectroscopy to measure the translational and rotational temperature of buffer-gas cooled molecules and demonstrate its use on hydrogen cyanide. This instrument can access the near-infrared region around 1.5 μm—a rich spectral region that features the rotationally resolved first overtone of the C-H stretch for many astrophysically relevant molecules. Molecules are probed directly inside the buffer-gas cell, further enabling quantitative measurements of the effectiveness of this cooling technique.
{"title":"Buffer-gas cooling of hydrogen cyanide quantified by cavity-ringdown spectroscopy","authors":"Thomas Howard, Shannon E. Ganley, Sanjana Maheshwari, Leah G. Dodson","doi":"10.1016/j.jms.2024.111953","DOIUrl":"10.1016/j.jms.2024.111953","url":null,"abstract":"<div><div>We describe an instrument that uses continuous-wave (CW) cavity-ringdown spectroscopy to measure the translational and rotational temperature of buffer-gas cooled molecules and demonstrate its use on hydrogen cyanide. This instrument can access the near-infrared region around 1.5 μm—a rich spectral region that features the rotationally resolved first overtone of the C-H stretch for many astrophysically relevant molecules. Molecules are probed directly inside the buffer-gas cell, further enabling quantitative measurements of the effectiveness of this cooling technique.</div></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"406 ","pages":"Article 111953"},"PeriodicalIF":1.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535260","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}
Pub Date : 2024-11-01Epub Date: 2024-10-16DOI: 10.1016/j.jms.2024.111955
D.M. Plastinina , A.S. Lipskaya , E.N. Chesnokov
The frequencies of C2HD hot bands ro-vibrational lines of the first overtone of C-H stretching were measured using tunable diode lasers. To expand the measuring range to the region of the large rotational numbers, a heated gas cell was used. Measurements were made in the range R1–R36 and P2–P14 for the transition (2,0,0,1,0) ← (0,0,0,1,0), and in the range R1–R18 for the transition (2,0,0,0,1) ← (0,0,0,0,1). The rotational parameters of the upper and lower states for the band (2,0,0,1,0) ← (0,0,0,1,0) were determined. The doublet structure of ro-vibrational lines was studied. For the transition (2,0,0,1,0) ← (0,0,0,1,0), a sharp increase in the splitting value was detected at J > 25.
{"title":"High resolution laser diode spectroscopy of the hot bands of C2HD in the first overtone region of C-H stretching","authors":"D.M. Plastinina , A.S. Lipskaya , E.N. Chesnokov","doi":"10.1016/j.jms.2024.111955","DOIUrl":"10.1016/j.jms.2024.111955","url":null,"abstract":"<div><div>The frequencies of C<sub>2</sub>HD hot bands ro-vibrational lines of the first overtone of C-H stretching were measured using tunable diode lasers. To expand the measuring range to the region of the large rotational numbers, a heated gas cell was used. Measurements were made in the range R1–R36 and P2–P14 for the transition (2,0,0,1,0) ← (0,0,0,1,0), and in the range R1–R18 for the transition (2,0,0,0,1) ← (0,0,0,0,1). The rotational parameters of the upper and lower states for the band (2,0,0,1,0) ← (0,0,0,1,0) were determined. The doublet structure of ro-vibrational lines was studied. For the transition (2,0,0,1,0) ← (0,0,0,1,0), a sharp increase in the splitting value was detected at J > 25.</div></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"406 ","pages":"Article 111955"},"PeriodicalIF":1.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535262","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}
Pub Date : 2024-11-01Epub Date: 2024-10-11DOI: 10.1016/j.jms.2024.111954
Zbigniew Kisiel
<div><div>The present work fills several significant gaps in the study of the rotational spectrum of the methylene chloride molecule. Two Fourier transform microwave spectrometers were used, providing complementary coverage of the 8–18 GHz region, at room temperature and in supersonic expansion. Hyperfine resolved measurements were made and fitted for ground states of the CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<sup>37</sup>Cl, CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>37</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and <sup>13</sup>CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> isotopic species, as well as for nine different excited vibrational states. Transitions in the <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>2</mn></mrow></math></span>, <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>3</mn></mrow></math></span>, <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>=</mo><mn>1</mn></mrow></math></span>, <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>9</mn></mrow></msub><mo>=</mo><mn>1</mn></mrow></math></span> states in CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and transitions in excited states of the <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> mode in <sup>35</sup>Cl<sup>37</sup>Cl and <sup>37</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> isotopic species have been assigned for the first time. Vibrational and isotopic dependence of nuclear quadrupole coupling constants was identified. The <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>=</mo><mn>1</mn></mrow></math></span> and <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>9</mn></mrow></msub><mo>=</mo><mn>1</mn></mrow></math></span> states in CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> were found to be significantly coupled by <span><math><mi>c</mi></math></span>-axis Coriolis interaction, while transitions in <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>2</mn></mrow></math></span> and <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>3</mn></mrow></math></span> states exhibited hyperfine mediated p
{"title":"Isotopic species, vibrational states and nuclear quadrupole splitting in CH2Cl2 from rotational spectroscopy at 8–18 GHz","authors":"Zbigniew Kisiel","doi":"10.1016/j.jms.2024.111954","DOIUrl":"10.1016/j.jms.2024.111954","url":null,"abstract":"<div><div>The present work fills several significant gaps in the study of the rotational spectrum of the methylene chloride molecule. Two Fourier transform microwave spectrometers were used, providing complementary coverage of the 8–18 GHz region, at room temperature and in supersonic expansion. Hyperfine resolved measurements were made and fitted for ground states of the CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<sup>37</sup>Cl, CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>37</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and <sup>13</sup>CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> isotopic species, as well as for nine different excited vibrational states. Transitions in the <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>2</mn></mrow></math></span>, <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>3</mn></mrow></math></span>, <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>=</mo><mn>1</mn></mrow></math></span>, <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>9</mn></mrow></msub><mo>=</mo><mn>1</mn></mrow></math></span> states in CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and transitions in excited states of the <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> mode in <sup>35</sup>Cl<sup>37</sup>Cl and <sup>37</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> isotopic species have been assigned for the first time. Vibrational and isotopic dependence of nuclear quadrupole coupling constants was identified. The <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>=</mo><mn>1</mn></mrow></math></span> and <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>9</mn></mrow></msub><mo>=</mo><mn>1</mn></mrow></math></span> states in CH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span><sup>35</sup>Cl<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> were found to be significantly coupled by <span><math><mi>c</mi></math></span>-axis Coriolis interaction, while transitions in <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>2</mn></mrow></math></span> and <span><math><mrow><msub><mrow><mi>v</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>=</mo><mn>3</mn></mrow></math></span> states exhibited hyperfine mediated p","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"406 ","pages":"Article 111954"},"PeriodicalIF":1.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535263","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}
Pub Date : 2024-11-01Epub Date: 2024-11-15DOI: 10.1016/j.jms.2024.111956
Jonathan R. Dotson, C. Zachary Palmer, Ryan C. Fortenberry
Nitrogen’s introduction into the Earth’s atmosphere may stem from interstellar dust particles delivering some form of nitrogen species at the dawn of the planet’s formation. One contributing source of the present nitrogen may be elusive aluminum nitride molecular clusters that are believed to be included within protoplanetary carbonaceous chondritic meteors. The present work utilizes explicitly correlated coupled cluster theory within theoretical spectroscopic techniques to provide rovibrational spectral data for small, cyclic aluminum nitride cluster conformers in the hopes of aiding in searches for such elusive molecules. The most intense transitions for each cluster are the AlH stretches within the 5.2 range with the most intense transition of 584 km mol−1 exhibited by -AlNH. Many clusters investigated herein also possess large dipole moments such as 4.45 D from NH in its C conformation. The intense vibrational transitions and large dipole moments for the molecules studied in this work should be instrumental for the rotational, vibrational, or rovibrational detection of aluminum nitride clusters that may shed light on the origin of the nitrogen present within the Earth’s atmosphere and may hold keys for observing other planet-forming regions.
氮进入地球大气层可能是由于在地球形成之初星际尘埃粒子提供了某种形式的氮物种。目前氮的一个来源可能是难以捉摸的氮化铝分子簇，据信这些分子簇包含在原行星碳质软玉流星中。本研究利用理论光谱学技术中的显相关耦合团簇理论，提供了小型环状氮化铝团簇构象的振动光谱数据，希望能有助于寻找这类难以捉摸的分子。每个簇最强烈的转变是 5.2-5.6μm 范围内的 Al-H 伸展，c-Al3NH4 的最强烈转变为 584 km mol-1。本文研究的许多团簇还具有较大的偶极矩，例如 C2v 构象中的 c-N4H4 具有 4.45 D 的偶极矩。这项工作中研究的分子的强烈振动转变和大偶极矩应有助于对氮化铝团簇进行旋转、振动或滚振探测，从而揭示地球大气中氮元素的来源，并为观测其他行星形成区域提供关键信息。
{"title":"Spectral features for systematic aluminum replacement in N2H2 and c-N4H4 isomers","authors":"Jonathan R. Dotson, C. Zachary Palmer, Ryan C. Fortenberry","doi":"10.1016/j.jms.2024.111956","DOIUrl":"10.1016/j.jms.2024.111956","url":null,"abstract":"<div><div>Nitrogen’s introduction into the Earth’s atmosphere may stem from interstellar dust particles delivering some form of nitrogen species at the dawn of the planet’s formation. One contributing source of the present nitrogen may be elusive aluminum nitride molecular clusters that are believed to be included within protoplanetary carbonaceous chondritic meteors. The present work utilizes explicitly correlated coupled cluster theory within theoretical spectroscopic techniques to provide rovibrational spectral data for small, cyclic aluminum nitride cluster conformers in the hopes of aiding in searches for such elusive molecules. The most intense transitions for each cluster are the Al<span><math><mo>−</mo></math></span>H stretches within the 5.2<span><math><mrow><mo>−</mo><mn>5</mn><mo>.</mo><mn>6</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> range with the most intense transition of 584 km mol<sup>−1</sup> exhibited by <span><math><mi>c</mi></math></span>-Al<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>NH<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>. Many clusters investigated herein also possess large dipole moments such as 4.45 D from <span><math><mrow><mi>c</mi><mo>−</mo></mrow></math></span>N<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> in its C<span><math><msub><mrow></mrow><mrow><mn>2</mn><mi>v</mi></mrow></msub></math></span> conformation. The intense vibrational transitions and large dipole moments for the molecules studied in this work should be instrumental for the rotational, vibrational, or rovibrational detection of aluminum nitride clusters that may shed light on the origin of the nitrogen present within the Earth’s atmosphere and may hold keys for observing other planet-forming regions.</div></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"406 ","pages":"Article 111956"},"PeriodicalIF":1.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699147","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}
Pub Date : 2024-10-01Epub Date: 2024-10-02DOI: 10.1016/j.jms.2024.111951
Nan Fang , Chuan-Yu Zhang , Ming-Jie Wan , Xiao-Peng Huang
The molecular potential energy function plays an important role in many fields. In this paper, the icMRCI + Q method was utilized to compute the potential energy and dipole moments for 22 Λ-S states and 51 Ω states of the TeI+ system. Two basis sets (AVQZ-PP and AWCVQZ-PP) were employed to compute the TeI+ system, with the results indicating that the AVQZ-PP basis set yielded more accurate results. Therefore, all calculations in this paper are based on this basis set. Furthermore, to ensure the accuracy of the results, a comparison was conducted on the spectral parameters of the ground state and two excited states of the molecular ion within the same main group. Given the significant impact of spin–orbit coupling, as indicated by the calculated SO matrix elements, our discussion will predominantly center on the avoidance of crossovers in the Ω states. Finally, the Franck-Condon factors, Einstein coefficients and radiative lifetime between these two states were calculated from the data of the transition between the of the TeI+ molecule.
{"title":"Theoretical study on the spectrum properties of tellurium iodide cation","authors":"Nan Fang , Chuan-Yu Zhang , Ming-Jie Wan , Xiao-Peng Huang","doi":"10.1016/j.jms.2024.111951","DOIUrl":"10.1016/j.jms.2024.111951","url":null,"abstract":"<div><div>The molecular potential energy function plays an important role in many fields. In this paper, the icMRCI + Q method was utilized to compute the potential energy and dipole moments for 22 Λ-S states and 51 Ω states of the TeI<sup>+</sup> system. Two basis sets (AVQZ-PP and AWCVQZ-PP) were employed to compute the TeI<sup>+</sup> system, with the results indicating that the AVQZ-PP basis set yielded more accurate results. Therefore, all calculations in this paper are based on this basis set. Furthermore, to ensure the accuracy of the results, a comparison was conducted on the spectral parameters of the ground state and two excited states of the molecular ion within the same main group. Given the significant impact of spin–orbit coupling, as indicated by the calculated SO matrix elements, our discussion will predominantly center on the avoidance of crossovers in the Ω states. Finally, the Franck-Condon factors, Einstein coefficients and radiative lifetime between these two states were calculated from the data of the transition between the <span><math><mrow><msup><mi>X</mi><mn>3</mn></msup><msubsup><mi>Σ</mi><mrow><msup><mn>0</mn><mo>+</mo></msup></mrow><mo>-</mo></msubsup><mo>↔</mo><msup><mn>1</mn><mn>1</mn></msup><msubsup><mi>Σ</mi><mrow><msup><mn>0</mn><mo>+</mo></msup></mrow><mo>+</mo></msubsup></mrow></math></span> of the TeI<sup>+</sup> molecule.</div></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"405 ","pages":"Article 111951"},"PeriodicalIF":1.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426406","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}
Pub Date : 2024-10-01Epub Date: 2024-09-24DOI: 10.1016/j.jms.2024.111949
Adam M. Daly , Kristen K. Roehling , Rhett P. Hill , Myla G. Gonzalez , Xin Kang , Lisa McElwee-White , Stephen G. Kukolich
The microwave spectrum of η4-butadiene ruthenium tricarbonyl was measured in the 5–15 GHz frequency range using a Flygare-Balle type pulsed beam Fourier transform microwave (FTMW) spectrometer. The rotational constants for the 102Ru isotopologue were determined to have the following values: A = 932.20099(42), B = 858.03248(47) and C = 831.35161(37) MHz. The centrifugal distortion constant dJ is 0.0862(29)kHz. 22 a-dipole and 4c-dipole transitions were measured. Extensive high-level G16 calculations were made using DFT and MP2 methods with various basis sets, some including core-potentials (ECP). The best structure was calculated with Gaussian 16 using B3LYP/def2-QZVPP, which includes a core potential (ECP). Extensive all-electron calculations were made based on the best ECP structure to predict 101Ru and 99Ru quadrupole coupling strengths. Quadrupole hyperfine structure splittings were measured for both 101Ru and 99Ru. The hyperfine structure splittings for the 101Ru nuclear quadrupole were measured, yielding the values of 1.5χaa = 98.12(17) MHz and 0.25(χbb-χcc) = 36.059(30). Measured hyperfine structure splittings for 99Ru quadrupole coupling yielded the values of 1.5χaa = 16.99(77) MHz and 0.25(χbb-χcc) = 6.23(32). These values are in reasonable agreement with some of the all-electron calculations.
{"title":"Microwave spectrum and molecular structure calculations for η4-butadiene ruthenium tricarbonyl","authors":"Adam M. Daly , Kristen K. Roehling , Rhett P. Hill , Myla G. Gonzalez , Xin Kang , Lisa McElwee-White , Stephen G. Kukolich","doi":"10.1016/j.jms.2024.111949","DOIUrl":"10.1016/j.jms.2024.111949","url":null,"abstract":"<div><div>The microwave spectrum of η<sup>4</sup>-butadiene ruthenium tricarbonyl was measured in the 5–15 GHz frequency range using a Flygare-Balle type pulsed beam Fourier transform microwave (FTMW) spectrometer. The rotational constants for the <sup>102</sup>Ru isotopologue were determined to have the following values: A = 932.20099(42), B = 858.03248(47) and C = 831.35161(37) MHz. The centrifugal distortion constant d<sub>J</sub> is 0.0862(29)kHz. 22 a-dipole and 4c-dipole transitions were measured. Extensive high-level G16 calculations were made using DFT and MP2 methods with various basis sets, some including core-potentials (ECP). The best structure was calculated with Gaussian 16 using B3LYP/def2-QZVPP, which includes a core potential (ECP). Extensive all-electron calculations were made based on the best ECP structure to predict <sup>101</sup>Ru and <sup>99</sup>Ru quadrupole coupling strengths. Quadrupole hyperfine structure splittings were measured for both <sup>101</sup>Ru and <sup>99</sup>Ru. The hyperfine structure splittings for the <sup>101</sup>Ru nuclear quadrupole were measured, yielding the values of 1.5χ<sub>aa</sub> = 98.12(17) MHz and 0.25(χ<sub>bb</sub>-χ<sub>cc</sub>) = 36.059(30). Measured hyperfine structure splittings for <sup>99</sup>Ru quadrupole coupling yielded the values of 1.5χ<sub>aa</sub> = 16.99(77) MHz and 0.25(χ<sub>bb</sub>-χ<sub>cc</sub>) = 6.23(32). These values are in reasonable agreement with some of the all-electron calculations.</div></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":"405 ","pages":"Article 111949"},"PeriodicalIF":1.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327336","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}
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