OH stretching frequencies in systems with intramolecular hydrogen bonds: Harmonic and anharmonic analyses

► Stretching wavenumbers for intramolecularly hydrogen-bonded OH groups. ► Harmonic and second order perturbation theory anharmonic approximations. ► Computed harmonic and anharmonic wavenumbers linearly related. ► Linear correlations between observed and computed wavenumbers. ► Linear correlation with OH proton NMR chemical shifts.