{"title":"Isotopic species, vibrational states and nuclear quadrupole splitting in CH2Cl2 from rotational spectroscopy at 8–18 GHz","authors":"","doi":"10.1016/j.jms.2024.111954","DOIUrl":null,"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 perturbations enhancing the determination of the <span><math><msub><mrow><mi>χ</mi></mrow><mrow><mi>a</mi><mi>b</mi></mrow></msub></math></span> parameter and allowing assessment of its vibrational dependence.</div></div>","PeriodicalId":16367,"journal":{"name":"Journal of Molecular Spectroscopy","volume":null,"pages":null},"PeriodicalIF":1.4000,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Molecular Spectroscopy","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S002228522400081X","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PHYSICS, ATOMIC, MOLECULAR & CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
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 CH35Cl, CH35Cl37Cl, CH37Cl, and 13CH35Cl isotopic species, as well as for nine different excited vibrational states. Transitions in the , , , states in CH35Cl, and transitions in excited states of the mode in 35Cl37Cl and 37Cl isotopic species have been assigned for the first time. Vibrational and isotopic dependence of nuclear quadrupole coupling constants was identified. The and states in CH35Cl were found to be significantly coupled by -axis Coriolis interaction, while transitions in and states exhibited hyperfine mediated perturbations enhancing the determination of the parameter and allowing assessment of its vibrational dependence.
期刊介绍:
The Journal of Molecular Spectroscopy presents experimental and theoretical articles on all subjects relevant to molecular spectroscopy and its modern applications. An international medium for the publication of some of the most significant research in the field, the Journal of Molecular Spectroscopy is an invaluable resource for astrophysicists, chemists, physicists, engineers, and others involved in molecular spectroscopy research and practice.