Ring currents and their effects in aromatic molecules

Abstract

The form of the localized orbitals needed to describe the properties of an aromatic molecule in the presence of a magnetic field is discussed using the standard excited state. The ring currents induced by an external field give rise to contributions to the diamagnetic anisotropy and to the shielding of the nuclear dipole of an attached proton. Both of these effects are calculated on the basis of the self-consistent form of molecular orbital theory. For this purpose the perturbation equations are solved iteratively and results are given for some hydrocarbon molecules.