Rotational spectroscopy update for the newly identified atmospheric ozone depleter CF3CCl3

Abstract The pure rotational spectrum of CF 3 CCl 3 (1,1,1-trichloro-2,2,2-trifluoroethane, CFC-113a) was investigated at 4–18 GHz in supersonic expansion with chirped pulse and cavity Fourier-transform rotational spectroscopy, and at 94–309 GHz with broadband millimetre wave spectroscopy. Spectroscopic constants for all four possible chlorine isotopic species have been considerably updated. Global fits of hyperfine-resolved and hyperfine-unresolved data are reported and triple chlorine nucleus hyperfine structure has been analysed for all four isotopologues to within experimental accuracy. The new measurements have been augmented with anharmonic force field calculations in an evaluation of the semi-experimental equilibrium geometry for CF 3 CCl 3 . Interactions between hyperfine sublevels contributing to frequencies of the lowest J transitions allowed determination of the axial rotational constant A  = 1326.24(15) MHz for CF 3 C 35 Cl 3 from analysis of pure rotational transitions.