Reference data for isolated eugenol

This dataset contains the computational and spectroscopic data supporting the investigation of the rotational spectrum of eugenol (2-methoxy-4-(prop-2-en-1-yl)phenol). The conformational space is explored using density functional theory (DFT) at the B3LYP-D3(BJ)/6-31G(d) and B3LYP-D3(BJ)/def2-TZVP level of calculations. Twelve non-equivalent minima are characterized, as well as the interconversion pathways between the hydrogen-bonded forms. All the computational output files are provided. The R-mub-type spectra of three hydrogen-bonded species (HB) with either an extended (E) or folded (F) orientation of the allyl frame are assigned in the experimental free-jet absorption Stark-modulated spectrum: HB-E1, HB-F, HB-E2. For the global minimum (HB-E1), previously reported microwave data (3–18 GHz) are taken into account. All the input and output fitting files in the Watson's S-reduction and the I-r representation are provided.