Rotational spectroscopy of isotopic cyclopropenone, $c$-H${}_2$C${}_3$O, and determination of its equilibrium structure

Abstract

Cyclopropenone was first detected in the cold and less dense envelope of Sagittarius B2(N). It was found later in several cold dark clouds and it may be possible to detect its minor isotopic species in these environments. In addition, the main species may well be identified in warmer environments. We aim to extend existing line lists of isotopologs of c-H2C3O from the microwave to the millimeter region and create one for the singly deuterated isotopolog to facilitate their detections in space. Furthermore, we aim to extend the line list of the main isotopic species to the submillimeter region and to evaluate an equilibrium structure of the molecule. We employed a cyclopropenone sample in natural isotopic composition to investigate the rotational spectra of the main and 18O-containing isotopologs as well as the two isotopomers containing one 13C atom. Spectral recordings of the singly and doubly deuterated isotopic species were obtained using a cyclopropenone sample highly enriched in deuterium. We recorded rotational transitions in the 70-126 GHz and 160-245 GHz regions for all isotopologs and also in the 342-505 GHz range for the main species. Quantum-chemical calculations were carried out to evaluate initial spectroscopic parameters and the differences between ground-state and equilibrium rotational parameters in order to derive semi-empirical equilibrium structural parameters. We determined new or improved spectroscopic parameters for six isotopologs and structural parameters according to different structure models. The spectroscopic parameters are accurate enough to identify minor isotopic species at centimeter and millimeter wavelengths while those of the main species are deemed to be reliable up to 1 THz. Our structural parameters differ from earlier ones. The deviations are attributed to misassignments in the earlier spectrum of one isotopic species.

arXiv comment11 pages; abstract slightly abbreviated; Astron. Astrophys., in press

References in corpus (10)

• Exploring molecular complexity with ALMA (EMoCA): Alkanethiols and alkanols in Sagittarius B2(N2)
• The ALMA-PILS survey: First detections of ethylene oxide, acetone and propanal toward the low-mass protostar IRAS 16293-2422
• The interstellar chemistry of H2C3O isomers
• Discovery of HC3O+ in space: The chemistry of O-bearing species in TMC-1
• Rotational spectroscopy of isotopic vinyl cyanide, H${}_2$C=CH$-$C$\equiv$N, in the laboratory and in space
• The ALMA-PILS survey: First detection of the unsaturated 3-carbon molecules Propenal (C${}_2$H${}_3$CHO) and Propylene (C${}_3$H${}_6$) towards IRAS 16293$-$2422 B
• A study of the C${}_3$H${}_2$ isomers and isotopologues: first interstellar detection of HDCCC
• First detection of 13CH in the interstellar medium
• Laboratory spectroscopic study of isotopic thioformaldehyde, H${}_2$CS, and determination of its equilibrium structure
• The quest for complex molecules in space: Laboratory spectroscopy of n-butyl cyanide, n-C4H9CN, in the millimeter wave region and its astronomical search in Sagittarius B2(N)

Cited by in corpus (4)

• Rotational spectroscopy of mono-deuterated oxirane ($c$-C${}_2$H${}_3$DO) and its detection towards IRAS 16293$-$2422 B
• Rotational spectroscopy of isotopic oxirane, $c$-C${}_2$H${}_4$O
• Rotational spectroscopy of oxirane-\textit{2,2}-$d_2$, $c$-CD${}_2$CH${}_2$O, and its tentative detection toward IRAS 16293$-$2422~B
• Rotational spectroscopy of the thioformaldehyde isotopologues H${}_2$CS and H${}_2$C${}^{34}$S in four interacting excited vibrational states and an account on the rotational spectrum of thioketene, H${}_2$CCS