Rotational spectrum of trifluoroacetic acid: Extension of the measurements by chirped-pulse spectroscopy

The rotational spectrum of trifluoroacetic acid has been recorded at room temperature in the 18–26 GHz frequency range using a chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer. More than 180 new spectral lines have been identified and assigned to transitions within the vibrational ground state. A global fitting has been performed by incorporating spectroscopic data from previous studies, leading to the refinement of the molecular parameters. Two fitting models using Watson’s S -reduction and A -reduction are proposed, allowing the determination of h 3 for the first model and Φ J K , Φ K J , and ϕ K for the second one. • Room-temperature chirped-pulse spectrum in the 18–26 GHz region. • New rotational data on the smallest perfluoroalkyl carboxylic acid. • Global rotational fit for trifluoroacetic acid. • Good accuracy of MP2/aug-cc-pVTZ calculated spectroscopic parameters.