Laboratory Measurement of CH2DOH Line Intensities in the Millimeter-wave Region
Deuterium fractionation in molecules is known as one of the most powerful tools to study chemical processes during star and planet formation. Among various interstellar molecules, methanol often shows very high deuterium fractionation. It is the most abundant saturated organic molecule and is known...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acf320 |
| _version_ | 1797656005564170240 |
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| author | Takahiro Oyama Yuki Ohno Akemi Tamanai Yoshimasa Watanabe Satoshi Yamamoto Takeshi Sakai Shaoshan Zeng Riouhei Nakatani Nami Sakai |
| author_facet | Takahiro Oyama Yuki Ohno Akemi Tamanai Yoshimasa Watanabe Satoshi Yamamoto Takeshi Sakai Shaoshan Zeng Riouhei Nakatani Nami Sakai |
| author_sort | Takahiro Oyama |
| collection | DOAJ |
| description | Deuterium fractionation in molecules is known as one of the most powerful tools to study chemical processes during star and planet formation. Among various interstellar molecules, methanol often shows very high deuterium fractionation. It is the most abundant saturated organic molecule and is known as a parent species to form more complex organic molecules. However, deriving the abundance of deuterated methanol suffers from the uncertainty in the intrinsic line intensities ( S μ ^2 ) of CH _3 OH isotopologues. Due to their floppy nature, theoretical evaluation of the S μ ^2 values is not straightforward, particularly for asymmetric-top asymmetric-frame isotopologues such as CH _2 DOH. In this study, we have measured the line frequencies and their intensities for CH _2 DOH in the millimeter-wave region from 216 to 264 GHz by using an emission-type millimeter and submillimeter-wave spectrometer. For the a -type J = 5 − 4 transition, the derived S μ ^2 values are 13%–27% larger than those theoretically calculated, except for the transitions of K _a = 2 for e _0 and K _a = 1 for e _1 affected by avoided level crossing. For b -type transitions, significant systematic differences are found between theoretical and experimental S μ ^2 values. The results of the present study enable us to accurately derive from observations the CH _2 DOH abundances, which are essential for understanding deuterium fractionation in various sources. |
| first_indexed | 2024-03-11T17:22:54Z |
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| id | doaj.art-b791a2176dc8464ba38b492e0535b136 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-11T17:22:54Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-b791a2176dc8464ba38b492e0535b1362023-10-19T08:28:18ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-019571410.3847/1538-4357/acf320Laboratory Measurement of CH2DOH Line Intensities in the Millimeter-wave RegionTakahiro Oyama0https://orcid.org/0000-0002-2301-7951Yuki Ohno1https://orcid.org/0000-0002-5674-6624Akemi Tamanai2https://orcid.org/0000-0002-5430-1170Yoshimasa Watanabe3https://orcid.org/0000-0002-9668-3592Satoshi Yamamoto4https://orcid.org/0000-0002-9865-0970Takeshi Sakai5https://orcid.org/0000-0003-4521-7492Shaoshan Zeng6https://orcid.org/0000-0003-3721-374XRiouhei Nakatani7https://orcid.org/0000-0002-1803-0203Nami Sakai8https://orcid.org/0000-0002-3297-4497RIKEN Cluster for Pioneering Research , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan ; takahiro.oyama@riken.jpRIKEN Cluster for Pioneering Research , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan ; takahiro.oyama@riken.jp; Department of Chemistry, Faculty of Science Division I, Tokyo University of Science , 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, JapanRIKEN Cluster for Pioneering Research , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan ; takahiro.oyama@riken.jpRIKEN Cluster for Pioneering Research , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan ; takahiro.oyama@riken.jp; Materials Science and Engineering, College of Engineering, Shibaura Institute of Technology , 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, JapanResearch Center for the Early Universe, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; SOKENDAI , Shonan Village, Hayama, Kanagawa 240-0193, JapanGraduate School of Informatics and Engineering, The University of Electro-Communications , Chofu, Tokyo 182-8585, JapanRIKEN Cluster for Pioneering Research , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan ; takahiro.oyama@riken.jpRIKEN Cluster for Pioneering Research , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan ; takahiro.oyama@riken.jp; NASA Jet Propulsion Laboratory , California Institute of Technology, Pasadena, CA 91109, USARIKEN Cluster for Pioneering Research , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan ; takahiro.oyama@riken.jpDeuterium fractionation in molecules is known as one of the most powerful tools to study chemical processes during star and planet formation. Among various interstellar molecules, methanol often shows very high deuterium fractionation. It is the most abundant saturated organic molecule and is known as a parent species to form more complex organic molecules. However, deriving the abundance of deuterated methanol suffers from the uncertainty in the intrinsic line intensities ( S μ ^2 ) of CH _3 OH isotopologues. Due to their floppy nature, theoretical evaluation of the S μ ^2 values is not straightforward, particularly for asymmetric-top asymmetric-frame isotopologues such as CH _2 DOH. In this study, we have measured the line frequencies and their intensities for CH _2 DOH in the millimeter-wave region from 216 to 264 GHz by using an emission-type millimeter and submillimeter-wave spectrometer. For the a -type J = 5 − 4 transition, the derived S μ ^2 values are 13%–27% larger than those theoretically calculated, except for the transitions of K _a = 2 for e _0 and K _a = 1 for e _1 affected by avoided level crossing. For b -type transitions, significant systematic differences are found between theoretical and experimental S μ ^2 values. The results of the present study enable us to accurately derive from observations the CH _2 DOH abundances, which are essential for understanding deuterium fractionation in various sources.https://doi.org/10.3847/1538-4357/acf320Molecular spectroscopyLine positionsLine intensitiesAstrochemistry |
| spellingShingle | Takahiro Oyama Yuki Ohno Akemi Tamanai Yoshimasa Watanabe Satoshi Yamamoto Takeshi Sakai Shaoshan Zeng Riouhei Nakatani Nami Sakai Laboratory Measurement of CH2DOH Line Intensities in the Millimeter-wave Region The Astrophysical Journal Molecular spectroscopy Line positions Line intensities Astrochemistry |
| title | Laboratory Measurement of CH2DOH Line Intensities in the Millimeter-wave Region |
| title_full | Laboratory Measurement of CH2DOH Line Intensities in the Millimeter-wave Region |
| title_fullStr | Laboratory Measurement of CH2DOH Line Intensities in the Millimeter-wave Region |
| title_full_unstemmed | Laboratory Measurement of CH2DOH Line Intensities in the Millimeter-wave Region |
| title_short | Laboratory Measurement of CH2DOH Line Intensities in the Millimeter-wave Region |
| title_sort | laboratory measurement of ch2doh line intensities in the millimeter wave region |
| topic | Molecular spectroscopy Line positions Line intensities Astrochemistry |
| url | https://doi.org/10.3847/1538-4357/acf320 |
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