Calculation of Nuclear Spin-Spin Coupling Constants in Methanol Molecule

The perturbed Hartree-Fock scheme is applied to rationalize the nuclear spin–spin coupling constants in methanol molecule. The theoretical predictions are partially successful, sign and relative magnitude of the various coupling constants being correctly estimated. The coupled HF method overestimates the Fermi contact contribution to total coupling constants, which is possibly due to electron correlation effects and to convergence problems of the perturbation scheme. The relative importance of the commonly neglected spin–orbit contribution is demonstrated. The dependence of computed values on the molecular configuration is discussed; the reliability of the geometric approximation to coupling constants is tested with good results for the spin–orbit contribution.