Nuclear spin coupling by electron orbital polarization

Abstract

A theory is presented of the coupling of nuclear spins in a molecule by the induction of electronic orbital currents. An approximate expression for the contribution of this effect to the total coupling constant is derived in terms of the anisotropy of the magnetic screening of the nuclei involved. The theory is applied to some coupling constants involving fluorine nuclei, for which the electron orbital contribution is found to be an appreciable but not dominant part. It can have either sign, but is usually positive.