Rotational spectroscopy of mono-deuterated oxirane ($c$-C${}_2$H${}_3$DO) and its detection towards IRAS 16293$-$2422 B

Abstract

We prepared a sample of mono-deuterated oxirane and studied its rotational spectrum in the laboratory between 490 GHz and 1060 GHz in order to improve its spectroscopic parameters and consequently the calculated rest frequencies of its rotational transitions. The updated rest frequencies were employed to detect $c$-C${}_2$H${}_3$DO for the first time in the interstellar medium in the Atacama Large Millimetre/submillimetre Array (ALMA) Protostellar Interferometric Line Survey (PILS) of the Class 0 protostellar system IRAS 16293$-$2422. Fits of the detected lines using the rotation diagrams yield a temperature of $T_{\mathrm{rot}}=103\pm 19$ K, which in turn agrees well with 125 K derived for the $c$-C${}_2$H${}_4$O main isotopologue previously. The $c$-C${}_2$H${}_3$DO to $c$-C${}_2$H${}_4$O ratio is found to be $\sim$0.15 corresponding to a D-to-H ratio of $\sim$0.036 per H atom which is slightly higher than the D-to-H ratio of species such as methanol, formaldehyde, ketene and but lower than those of the larger complex organic species such as ethanol, methylformate and glycolaldehyde. This may reflect that oxirane is formed fairly early in the evolution of the prestellar cores. The identification of doubly deuterated oxirane isotopomers in the PILS data may be possible judged by the amount of mono-deuterated oxirane and the observed trend that multiply deuterated isotopologues have higher deuteration rates than their mono-deuterated variants.

10 pages total; Mon. Not. R. Astron. Soc., accepted

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• Rotational spectroscopy of isotopic oxirane, $c$-C${}_2$H${}_4$O
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Cited by in corpus (9)

• A deep search for large complex organic species toward IRAS16293-2422 B at 3 mm with ALMA
• Rotational spectroscopy of CH${}_3$OD with a reanalysis of CH${}_3$OD toward IRAS 16293$-$2422
• Rotational spectroscopy of oxirane-\textit{2,2}-$d_2$, $c$-CD${}_2$CH${}_2$O, and its tentative detection toward IRAS 16293$-$2422~B
• Investigation of the rotational spectrum of CD${}_3$OD and an astronomical search toward IRAS 16293$-$2422
• Rotation-tunneling spectrum and astrochemical modeling of dimethylamine, CH${}_3$NHCH${}_3$, and searches for it in space
• The salty emission of the intermediate-mass AGB star OH 30.1 -0.7
• First detection of ethylene oxide and acetaldehyde in hot core G358.93$-$0.03 MM1: Tracing prebiotic oxygen chemistry
• Investigation of the rotational spectrum of CH${}_3$${}^{17}$OH and its tentative detection toward Sagittarius B2(N)
• Carbon chain diversity in L1544 and IRAS 16293-2422: an astrochemical pathfinder study for the SKAO