biostudies-literatureGupta DEuropean Research Council952-958https://www.ebi.ac.uk/biostudies/studies/S-EPMC12010422biostudies-literatureUnknown9(4)The rotationally resolved spectrum of the degenerate ν₄ antisymmetric C-H stretching band of the cyclopropenyl cation, c-C₃H₃ ⁺, the smallest aromatic hydrocarbon cation, has been recorded employing leak-out-spectroscopy (LOS) in a cryogenic 22-pole ion trap instrument operated at <i>T</i> = 42 K. About 370 lines were measured in the region 3110-3150 cm^-1 and assigned to rovibrational transitions of the fundamental antisymmetric C-H stretching band. Spectroscopic parameters have been refined compared to the previous experimental work from the group of Harold Linnartz [Zhao et al., <i>Astrophys. J. Lett.</i> 2014, 791, L28] and previous high-level theoretical predictions [Huang et al., <i>J. Phys. Chem. A</i> 2011, 115, 5005-5016]. DetaACS earth & space chemistryRotationally Resolved Spectrum of the Degenerate Antisymmetric C-H Stretching Band of c-C&lt;sub&gt;3&lt;/sub&gt;H&lt;sub&gt;3&lt;/sub&gt;<sup/>.PMC12010422101020583Schmid PCGupta DAsvany OSchlemmer SSalomon TfalseRotationally Resolved Spectrum of the Degenerate Antisymmetric C-H Stretching Band of c-C&lt;sub&gt;3&lt;/sub&gt;H&lt;sub&gt;3&lt;/sub&gt;<sup/>.The rotationally resolved spectrum of the degenerate ν₄ antisymmetric C-H stretching band of the cyclopropenyl cation, c-C₃H₃ ⁺, the smallest aromatic hydrocarbon cation, has been recorded employing leak-out-spectroscopy (LOS) in a cryogenic 22-pole ion trap instrument operated at <i>T</i> = 42 K. About 370 lines were measured in the region 3110-3150 cm^-1 and assigned to rovibrational transitions of the fundamental antisymmetric C-H stretching band. Spectroscopic parameters have been refined compared to the previous experimental work from the group of Harold Linnartz [Zhao et al., <i>Astrophys. J. Lett.</i> 2014, 791, L28] and previous high-level theoretical predictions [Huang et al., <i>J. Phys. Chem. A</i> 2011, 115, 5005-5016]. Deta2025-01-01T00:00:00Z2025 Apr2025-07-07T03:10:02.295Z2025-07-07T03:10:02.295ZS-EPMC120104224026481310.1021/acsearthspacechem.5c00032