Ab initio MO studies of nuclear spin–spin interactions in CH3F, SiH3F and CH3OH

Abstract

Ab initio molecular orbital calculations of indirect nuclear spin–spin coupling constants were carried out for CH₃F, SiH₃F and CH₃OH molecules employing the SCF perturbation theory. The basis set dependence of the four major contributing terms (orbital diamagnetic, orbital paramagnetic, spin dipolar and Fermi contact terms) are examined. The study also illustrates the importance of uncontracting the core functions and including bond functions and nuclear-centred polarization functions in the basis set. A satisfactory agreement is observed for most of the computed couplings with their experimental counterparts.