Determining the internal rotations of p-thiocresol

This Letter presents findings about the very low barriers hindering the internal rotations of p-thiocresol from microwave spectroscopy and ab initio calculations. tational spectrum of p-thiocresol has been studied using a Balle–Flygare type Fourier-transform microwave spectrometer. The assignment of the transitions allows the determination of rotational constants, centrifugal distortion constants, and the potential barrier hindering the internal rotations. -order Møller–Plesset perturbation theory (MP2) in connection with high-level basis sets has been used for the theoretical calculation of potential energies during the torsions of the functional groups and the determination of their equilibrium positions.