Field-Dependence of Chemical Shifts in Colbalt(III) N.M.R. Spectroscopy. Theoretical Predictions

Abstract

Ramsey's suggestion of fourth-order perturbation theory contribution to a field-dependent chemical shielding arising from paramagnetic currents is more closely examined. The effect is shown to be opposite in sign to the field-invariant chemical shielding tensor and, for cobalt(111) chemical shifts, only becomes important for some complexes for field strengths in excess of 20T.