On the relativistic molecular orbital theory of diamagnetism and NMR chemical shifts

Abstract

A relativistic molecular-orbital theory, analogous to the non-relativistic one of Pople (1962), has been formulated for the diamagnetic behaviour of electrons in the presence of an applied magnetic field. The molecular orbitals are written as linear combinations of gauge-invariant four spinors. A semi-empirical approach using Hückel-type approximations is employed. A similar treatment is developed for nuclear shielding tensors.