Abstract: The rovibrationally resolved Fourier transform (FT) far infrared (FIR) spectra of two intermolecular librations of (HF)3, namely the in-plane ν6 and out-of-plane ν4 bending fundamentals centered, respectively, at about 494 cm−1 and 602 cm−1, have been recorded for the first time under jet-cooled conditions using the supersonic jet of the Jet-AILES apparatus...