molecules:ism:methylformiat

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision		 Previous revision
molecules:ism:methylformiat [2019/03/14 11:59] – fixed characters adminmolecules:ism:methylformiat [2019/10/24 09:38] (current) – mueller
Line 3: Line 3:
 Methyl formate, HC(O)OCH<sub>3</sub>, is a typical hot core molecule. It is very abundant in massive star-forming regions. It was detected first in emission in Sgr B2 by\\ Methyl formate, HC(O)OCH<sub>3</sub>, is a typical hot core molecule. It is very abundant in massive star-forming regions. It was detected first in emission in Sgr B2 by\\
 R. D. Brown, J. G. Crofts, P. D. Godfrey, F. F. Gardner, B. J. Robinson, and J. B. Whiteoak,\\ R. D. Brown, J. G. Crofts, P. D. Godfrey, F. F. Gardner, B. J. Robinson, and J. B. Whiteoak,\\
-**[[http://cdsads.u-strasbg.fr/abs/1975ApJ...197L..29B|Discovery of Interstellar Methyl Formate]]**\\+**[[https://ui.adsabs.harvard.edu/abs/1975ApJ...197L..29B|Discovery of Interstellar Methyl Formate]]**\\
 //Astrophys. J.// **197**, L29–L31 (1975).\\ //Astrophys. J.// **197**, L29–L31 (1975).\\
 The //A// component of the 1<sub>10</sub> – 1<sub>11</sub> near 1610 GHz was clearly seen with the Parkes 64 m telescope, and there was evidence for the //E// component close by.\\ The //A// component of the 1<sub>10</sub> – 1<sub>11</sub> near 1610 GHz was clearly seen with the Parkes 64 m telescope, and there was evidence for the //E// component close by.\\
Line 26: Line 26:
 More recently,\\ More recently,\\
 S. Takano, Y. Sakai, S. Kakimoto, M. Sasaki, and K. Kobayashi reported on the\\ S. Takano, Y. Sakai, S. Kakimoto, M. Sasaki, and K. Kobayashi reported on the\\
-**[[http://cdsads.u-strasbg.fr/abs/2012PASJ...64...89T|Detection of Methyl Formate in the Second Torsionally Excited State (//v<sub>t</sub>// = 2) in Orion KL]]**\\+**[[https://ui.adsabs.harvard.edu/abs/2012PASJ...64...89T|Detection of Methyl Formate in the Second Torsionally Excited State (//v<sub>t</sub>// = 2) in Orion KL]]**\\
 //Publ. Astron. Soc. Japan// **64**, Art. No. 89 (2012).\\ //Publ. Astron. Soc. Japan// **64**, Art. No. 89 (2012).\\
 Four new lines were observed newly with the Nobeyama 45 m radio telescope near 90 GHz together with several transitions of the ground and the first excited torsional state. 15 additional lines were detected in two published line surveys. The derived vibrational temperature of about 125 K was higher than the rotational temperature of around 50 K, possibly indicating infrared pumping. Since the torsional modes are rather weak, it may be more likely that infrared pumping took place via some small amplitude vibration and subsequent intermolecular energy redistribution. However, as the authors indicated, collisional excitation cannot be ruled out a being responsible for the vibrational temperature being apparently higher than the rotational one. Four new lines were observed newly with the Nobeyama 45 m radio telescope near 90 GHz together with several transitions of the ground and the first excited torsional state. 15 additional lines were detected in two published line surveys. The derived vibrational temperature of about 125 K was higher than the rotational temperature of around 50 K, possibly indicating infrared pumping. Since the torsional modes are rather weak, it may be more likely that infrared pumping took place via some small amplitude vibration and subsequent intermolecular energy redistribution. However, as the authors indicated, collisional excitation cannot be ruled out a being responsible for the vibrational temperature being apparently higher than the rotational one.
Line 63: Line 63:
 **[[https://doi.org/10.1051/0004-6361/201832844|The ALMA-PILS Survey: The First Detection of Doubly-deuterated Methyl Formate (CHD<sub>2</sub>OCHO) in the ISM]]**\\ **[[https://doi.org/10.1051/0004-6361/201832844|The ALMA-PILS Survey: The First Detection of Doubly-deuterated Methyl Formate (CHD<sub>2</sub>OCHO) in the ISM]]**\\
 //Astron. Astrophys.// **623** (2019) Art. No. A69.\\ //Astron. Astrophys.// **623** (2019) Art. No. A69.\\
-The isotopolog was detected to source B as well as to source A. The deuteration per H atom is about 12 and 8 %, respectively, considerably higher than about 6 and 28 %, respectively, for the singly deuterated isotopomers.+The isotopolog was detected toward source B as well as toward source A. The deuteration per H atom is about 12 and 8 %, respectively, considerably higher than about 6 and 28 %, respectively, for the singly deuterated isotopomers.
  
 The so-called //trans// conformer, with the carbonyl oxygen pointing away from the methyl group, is very much higher (about 25 kJ/mol or about 3000 K) in energy than the so-called //cis// conformer. Nevertheless, it has been characterized in the laboratory recently and was detected tentatively in the cooler, probably more diffuse parts of Sagittarius B2(N) where the chemistry deviates significantly from LTE. The work has been described by\\ The so-called //trans// conformer, with the carbonyl oxygen pointing away from the methyl group, is very much higher (about 25 kJ/mol or about 3000 K) in energy than the so-called //cis// conformer. Nevertheless, it has been characterized in the laboratory recently and was detected tentatively in the cooler, probably more diffuse parts of Sagittarius B2(N) where the chemistry deviates significantly from LTE. The work has been described by\\
Line 72: Line 72:
  
 ---- ----
 +
 Contributor(s): H. S. P. Müller; 02, 2007; 04, 2011; 07, 2012; 08, 2012; 11, 2016; 03, 2019 Contributor(s): H. S. P. Müller; 02, 2007; 04, 2011; 07, 2012; 08, 2012; 11, 2016; 03, 2019
 +
 ---- ----
  • molecules/ism/methylformiat.1552561165.txt.gz
  • Last modified: 2019/03/14 11:59
  • by admin