Correcting the classical dipolar demagnetizing field in solution NMR

Numerous observations of anomalous intermolecular multiple-quantum and cross correlation peaks in solution NMR have led to a variety of theoretical treatments, some involving radiation damping or modified classical Bloch equations, others involving full quantum mechanical derivations. We explore the theoretical underpinnings of the classical model, which invokes the dipolar demagnetizing field, and correct a significant omission in the original formulation which has been propagated in later papers. This correction gives good agreement between theory and experiment.