ELECTRONIC CURRENT-DENSITY INDUCED BY NUCLEAR MAGNETIC DIPOLES

Magnetic point-group symmetries of high order in molecules can be desc ribed via the electronic current density vector field induced by a set of ideal magnetic dipoles properly placed in space. The expression fo r the diamagnetic Larmor-type current density induced in the electrons of a molecule by intrinsic nuclear magnetic dipole moments can be obt ained via classical electrodynamics, but quantum mechanics is necessar y to account for other terms: the Ramsey relations for paramagnetic sp in-orbit, spin-dipolar, Fermi contact, and cross Fermi contact/spin-di polar contributions to (indirect) spin-spin nuclear magnetic coupling can be rewritten in terms of second-rank current density tensors. Maps of current densities induced by two nuclear dipoles could be used to visualize the electron coupled interaction between two nuclei and to r ationalize the coupling mechanism.