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molecules:ism:c2h [2019/02/25 22:38] 127.0.0.1 external edit |
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The ethynyl radical in its <sup>2</sup>Σ ground vibrational state was detected with the NRAO 11 m telescope in the four stronger of the six hyperfine components of the //N// = 1 – 0 rotational transitions near 87.4 GHz by\\ | The ethynyl radical in its <sup>2</sup>Σ ground vibrational state was detected with the NRAO 11 m telescope in the four stronger of the six hyperfine components of the //N// = 1 – 0 rotational transitions near 87.4 GHz by\\ | ||
K. D. Tucker, M. L. Kutner, and P. Thaddeus,\\ | K. D. Tucker, M. L. Kutner, and P. Thaddeus,\\ | ||
- | **[[http://cdsads.u-strasbg.fr/abs/1974ApJ...193L.115T|The Ethynyl Radical C<sub>2</sub>H – A New Interstellar Molecule]]**,\\ | + | **[[https://ui.adsabs.harvard.edu/abs/1974ApJ...193L.115T|The Ethynyl Radical C<sub>2</sub>H – A New Interstellar Molecule]]**,\\ |
//Astrophys. J.// **193** L115–L119 (1974)\\ | //Astrophys. J.// **193** L115–L119 (1974)\\ | ||
before it was actually detected in the laboratory. The identification was based on hyperfine parameters obtained from electron-spin resonance measurements of ethynyl isolated in argon matrices. The molecule is rather ubiquitous as it has been detected in several star-forming regions such as W3, Orion A, Sgr B2, Sgr A, of which several include photon-dominated regions (PDRs), most notably M17 SW. It has also been detected in the circumstellar envelope of the carbon-rich late-type star CW Leo, also known as IRC +10216. | before it was actually detected in the laboratory. The identification was based on hyperfine parameters obtained from electron-spin resonance measurements of ethynyl isolated in argon matrices. The molecule is rather ubiquitous as it has been detected in several star-forming regions such as W3, Orion A, Sgr B2, Sgr A, of which several include photon-dominated regions (PDRs), most notably M17 SW. It has also been detected in the circumstellar envelope of the carbon-rich late-type star CW Leo, also known as IRC +10216. | ||
A. Wootten, E. P. Bozyan, D. P. Garrett, R. B. Loren, and R. L. Snell reported on the\\ | A. Wootten, E. P. Bozyan, D. P. Garrett, R. B. Loren, and R. L. Snell reported on the\\ | ||
- | **[[http://cdsads.u-strasbg.fr/abs/1980ApJ...239..844W|Detection of C<sub>2</sub>H in Cold Dark Clouds]]**,\\ | + | **[[https://ui.adsabs.harvard.edu/abs/1980ApJ...239..844W|Detection of C<sub>2</sub>H in Cold Dark Clouds]]**,\\ |
//Astrophys. J.// **239** 944–854 (1980). | //Astrophys. J.// **239** 944–854 (1980). | ||
The radical was also observed in the diffuse medium by:\\ | The radical was also observed in the diffuse medium by:\\ | ||
L.-Å. Nyman,\\ | L.-Å. Nyman,\\ | ||
- | **[[http://cdsads.u-strasbg.fr/abs/1984A%26A...141..323N|Detection of CS and C<sub>2</sub>H in Absorption]]**,\\ | + | **[[https://ui.adsabs.harvard.edu/abs/1984A%26A...141..323N|Detection of CS and C<sub>2</sub>H in Absorption]]**,\\ |
//Astron. Astrophys.// **141** 323–327 (1984). | //Astron. Astrophys.// **141** 323–327 (1984). | ||
C<sub>2</sub>D was detected near 216.4 GHz with the 5 m MWO telescope toward Orion KL by:\\ | C<sub>2</sub>D was detected near 216.4 GHz with the 5 m MWO telescope toward Orion KL by:\\ | ||
F. Combes, F. Boulanger, P. J. Encrenaz, M. Gerin, M. Bogey, C. Demuynck, J. L. Destomb,\\ | F. Combes, F. Boulanger, P. J. Encrenaz, M. Gerin, M. Bogey, C. Demuynck, J. L. Destomb,\\ | ||
- | **[[http://cdsads.u-strasbg.fr/abs/1985A%26A...147L..25C|Detection of Interstellar CCD]]**,\\ | + | **[[https://ui.adsabs.harvard.edu/abs/1985A%26A...147L..25C|Detection of Interstellar CCD]]**,\\ |
//Astron. Astrophys.// **147** L25–L26 (1985). | //Astron. Astrophys.// **147** L25–L26 (1985). | ||
The detection of the <sup>13</sup>C isotopic species was reported in:\\ | The detection of the <sup>13</sup>C isotopic species was reported in:\\ | ||
A. H. Saleck, R. Simon, G. Winnewisser, J. G. A. Wouterloot,\\ | A. H. Saleck, R. Simon, G. Winnewisser, J. G. A. Wouterloot,\\ | ||
- | **[[http://dx.doi.org/10.1139/p94-098|Detection of Interstellar <sup>13</sup>CCH and C<sup>13</sup>CH]]**,\\ | + | **[[https://doi.org/10.1139/p94-098|Detection of Interstellar <sup>13</sup>CCH and C<sup>13</sup>CH]]**,\\ |
//Can. J. Phys.// **72** 747–754 (1994). | //Can. J. Phys.// **72** 747–754 (1994). | ||
Three out of four observable fine structure components of the //N// = 3 – 2 rotational transition of vibrationally excited C<sub>2</sub>H were reportedly not overlapped:\\ | Three out of four observable fine structure components of the //N// = 3 – 2 rotational transition of vibrationally excited C<sub>2</sub>H were reportedly not overlapped:\\ | ||
E. D. Tenenbaum, J. L. Dodd, S. N. Milam, N. J. Woolf, and L. M. Ziurys,\\ | E. D. Tenenbaum, J. L. Dodd, S. N. Milam, N. J. Woolf, and L. M. Ziurys,\\ | ||
- | **[[http://dx.doi.org/10.1088/2041-8205/720/1/L102|Comparative Spectra of Oxygen-rich Versus Carbon-rich Circumstellar Shells: VY Canis Majoris and IRC +10216 at 215-285 GHz]]**,\\ | + | **[[https://doi.org/10.1088/2041-8205/720/1/L102|Comparative Spectra of Oxygen-rich Versus Carbon-rich Circumstellar Shells: VY Canis Majoris and IRC +10216 at 215-285 GHz]]**,\\ |
//Astrophys. J.// **720** L102–L107 (2010).\\ | //Astrophys. J.// **720** L102–L107 (2010).\\ | ||
The features were detected in the outer part of the circumstellar envelope of CW Leo; hence, the detection must be facilitated by formation pumping or by IR pumping. | The features were detected in the outer part of the circumstellar envelope of CW Leo; hence, the detection must be facilitated by formation pumping or by IR pumping. | ||
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The //A// <sup>2</sup>Π – //X// <sup>2</sup>Σ<sup>+</sup> first excited electronic transition of C<sub>2</sub>H is distributed over at least 5 bands because of vibronic coupling of the //A// with various higher excited vibrational Π states of the ground electronic //X// state. Almost 30 lines belonging to two of the stronger bands were detected with the Mayall telescope near 4011 and 4108 cm<sup>–1</sup> in the outer region of the circumstellar envelope of CW Leo by\\ | The //A// <sup>2</sup>Π – //X// <sup>2</sup>Σ<sup>+</sup> first excited electronic transition of C<sub>2</sub>H is distributed over at least 5 bands because of vibronic coupling of the //A// with various higher excited vibrational Π states of the ground electronic //X// state. Almost 30 lines belonging to two of the stronger bands were detected with the Mayall telescope near 4011 and 4108 cm<sup>–1</sup> in the outer region of the circumstellar envelope of CW Leo by\\ | ||
J. J. Keady and K. H. Hinkle,\\ | J. J. Keady and K. H. Hinkle,\\ | ||
- | **[[http://cdsads.u-strasbg.fr/abs/1988ApJ...331..539K|C<sub>2</sub>H in the 2 micron Infrared Spectrum of IRC +10216]]**,\\ | + | **[[https://ui.adsabs.harvard.edu/abs/1988ApJ...331..539K|C<sub>2</sub>H in the 2 micron Infrared Spectrum of IRC +10216]]**,\\ |
//Astrophys. J.// **331** 539–546 (1988).\\ | //Astrophys. J.// **331** 539–546 (1988).\\ | ||
The rotational temperature of 12.5 ± 1.5 K suggests a peak abundance about 1200 stellar radii away from CW Leo, and the line intensities indicate a high fractional abundance with respect to H<sub>2</sub>. | The rotational temperature of 12.5 ± 1.5 K suggests a peak abundance about 1200 stellar radii away from CW Leo, and the line intensities indicate a high fractional abundance with respect to H<sub>2</sub>. | ||
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Contributor(s): H. S. P. Müller; 1, 2012 | Contributor(s): H. S. P. Müller; 1, 2012 | ||
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