Theory of NMR in the molecular ring Fe10

The proton nuclear spin-lattice relaxation rate in the molecular ring Fe10 is calculated by linear response theory, starting from the unperturbed eigenvalues and eigenvectors, and introducing dipolar superhyperfine interactions as a perturbation. A strong enhancement of the rate at critical values of the applied magnetic field, recently observed by solid-state NMR at low temperatures, is explained in terms of level crossing between states with |?S| = 1 and |?M| = 1. © 2001 Elsevier Science B.V. All rights reserved.