Rotational Spectrum Of Paracetamol

In this paper we report the first rotational spectrum of isolated paracetamol. Solid samples of paracetamol were vaporized by laser ablation, expanded in a supersonic jet and characterized by Fourier transform microwave spectroscopy in the 4-10 GHz frequency range. The spectra of a total of four conformers, two with a trans peptidic -CO-NH- functional group arrangement and two with a cis peptidic group arrangement have been observed for the first time. The identification of all the conformers was based on the comparison of the experimental rotational and N-14 quadrupole coupling constants with those predicted by ab initio calculations, and relative values of their electrical dipole moment components.