Possibility of Field-Dependent Nuclear Magnetic Shielding

Abstract

The possibility of an observable field dependence of the nuclear magnetic shielding in NMR experiments is discussed. It is shown that in most molecules such an effect should be unobservably small. However, in some molecules, especially where the magnetic shielding is abnormally large, it is possible that the field dependence of the shielding could be large enough to be observable. In NMR experiments of high accuracy in strong magnetic fields, the proportionality of the resonance frequency to the magnetic field should therefore not be automatically assumed, but should be experimentally verified.