DYNAMIC APPROACH TO LOCAL-POLARIZATION DISTRIBUTION AND NMR LINE-SHAPE IN DEUTERON GLASSES

The path-integral formulation of Glauber dynamics by Sommers is applied to calculate the deuteron NMR line shape in structural glasses such as Rb1-x(ND4)(x)D2PO4. The system is described by a classical pseudospin Ising model with infinite-range exchange interactions and quenched random electric fields. It is shown that in the fast-motion limit the NMR line shape is directly related to the average probability distribution of local deuteron polarization and that the observable truncated second moment of the NMR line M2tr is proportional to the Edwards-Anderson order parameter q(EA). Leading dynamic corrections due to the slowing down of deuteron jumps in the ergodic phase are evaluated, and the behavior of M2tr at the crossover between the fast- and the slow-motion regimes is discussed.