{"title":"H2CC分子旋转线的强度:解决试探性检测","authors":"M.K. Sharma , M. Sharma , S. Chandra","doi":"10.1016/j.molap.2018.06.001","DOIUrl":null,"url":null,"abstract":"<div><p>Though H<sub>2</sub>C, H<sub>2</sub>CCC, H<sub>2</sub>CCCC, H<sub>2</sub>CCO, H<sub>2</sub>CO, H<sub>2</sub><span>CS molecules have been identified in cool interstellar clouds, identification of H</span><sub>2</sub>CC is still awaited. Formation of H<sub>2</sub><span>CC in the interstellar medium<span> is quite probable as the cosmic abundance of carbon is 20 times larger than that of the sulphur, and the molecule H</span></span><sub>2</sub>CS has already been identified in the interstellar medium. To our knowledge, no laboratory study for H<sub>2</sub><span>CC is available in literature. Physical conditions in the interstellar medium are quite different as compared to those in a terrestrial laboratory. Using the rotational and centrifugal distortion constants for H</span><sub>2</sub>CC, we have calculated the energies of rotational levels and the strengths of lines between the levels up to 270 cm<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>. We have found that 88 and 87 lines of ortho-H<sub>2</sub>CC and para-H<sub>2</sub>CC, respectively have Einstein <em>A</em>-coefficient larger than 10<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></math></span> s<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>. These lines may help in the identification of H<sub>2</sub>CC in the interstellar medium. Tentative detection of H<sub>2</sub>CC has been addressed.</p></div>","PeriodicalId":44164,"journal":{"name":"Molecular Astrophysics","volume":"12 ","pages":"Pages 20-24"},"PeriodicalIF":0.0000,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molap.2018.06.001","citationCount":"7","resultStr":"{\"title\":\"Strengths of rotational lines from H2CC molecule: Addressing tentative detection\",\"authors\":\"M.K. Sharma , M. Sharma , S. Chandra\",\"doi\":\"10.1016/j.molap.2018.06.001\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Though H<sub>2</sub>C, H<sub>2</sub>CCC, H<sub>2</sub>CCCC, H<sub>2</sub>CCO, H<sub>2</sub>CO, H<sub>2</sub><span>CS molecules have been identified in cool interstellar clouds, identification of H</span><sub>2</sub>CC is still awaited. Formation of H<sub>2</sub><span>CC in the interstellar medium<span> is quite probable as the cosmic abundance of carbon is 20 times larger than that of the sulphur, and the molecule H</span></span><sub>2</sub>CS has already been identified in the interstellar medium. To our knowledge, no laboratory study for H<sub>2</sub><span>CC is available in literature. Physical conditions in the interstellar medium are quite different as compared to those in a terrestrial laboratory. Using the rotational and centrifugal distortion constants for H</span><sub>2</sub>CC, we have calculated the energies of rotational levels and the strengths of lines between the levels up to 270 cm<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>. We have found that 88 and 87 lines of ortho-H<sub>2</sub>CC and para-H<sub>2</sub>CC, respectively have Einstein <em>A</em>-coefficient larger than 10<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></math></span> s<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>. These lines may help in the identification of H<sub>2</sub>CC in the interstellar medium. Tentative detection of H<sub>2</sub>CC has been addressed.</p></div>\",\"PeriodicalId\":44164,\"journal\":{\"name\":\"Molecular Astrophysics\",\"volume\":\"12 \",\"pages\":\"Pages 20-24\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2018-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/j.molap.2018.06.001\",\"citationCount\":\"7\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Molecular Astrophysics\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2405675816300525\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"Physics and Astronomy\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Molecular Astrophysics","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2405675816300525","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"Physics and Astronomy","Score":null,"Total":0}
Strengths of rotational lines from H2CC molecule: Addressing tentative detection
Though H2C, H2CCC, H2CCCC, H2CCO, H2CO, H2CS molecules have been identified in cool interstellar clouds, identification of H2CC is still awaited. Formation of H2CC in the interstellar medium is quite probable as the cosmic abundance of carbon is 20 times larger than that of the sulphur, and the molecule H2CS has already been identified in the interstellar medium. To our knowledge, no laboratory study for H2CC is available in literature. Physical conditions in the interstellar medium are quite different as compared to those in a terrestrial laboratory. Using the rotational and centrifugal distortion constants for H2CC, we have calculated the energies of rotational levels and the strengths of lines between the levels up to 270 cm. We have found that 88 and 87 lines of ortho-H2CC and para-H2CC, respectively have Einstein A-coefficient larger than 10 s. These lines may help in the identification of H2CC in the interstellar medium. Tentative detection of H2CC has been addressed.
期刊介绍：
Molecular Astrophysics is a peer-reviewed journal containing full research articles, selected review articles, and thematic issues. Molecular Astrophysics is a new journal where researchers working in planetary and exoplanetary science, astrochemistry, astrobiology, spectroscopy, physical chemistry and chemical physics can meet and exchange their ideas. Understanding the origin and evolution of interstellar and circumstellar molecules is key to understanding the Universe around us and our place in it and has become a fundamental goal of modern astrophysics. Molecular Astrophysics aims to provide a platform for scientists studying the chemical processes that form and dissociate molecules, and control chemical abundances in the universe, particularly in Solar System objects including planets, moons, and comets, in the atmospheres of exoplanets, as well as in regions of star and planet formation in the interstellar medium of galaxies. Observational studies of the molecular universe are driven by a range of new space missions and large-scale scale observatories opening up. With the Spitzer Space Telescope, the Herschel Space Observatory, the Atacama Large Millimeter/submillimeter Array (ALMA), NASA''s Kepler mission, the Rosetta mission, and more major future facilities such as NASA''s James Webb Space Telescope and various missions to Mars, the journal taps into the expected new insights and the need to bring the various communities together on one platform. The journal aims to cover observational, laboratory as well as computational results in the galactic, extragalactic and intergalactic areas of our universe.
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