Anomalous property of the spin–spin relaxation of 27Al NMR in dehydrated zeolite A

Anomalous temperature dependence of T2 for 27Al NMR in dehydrated zeolite A is found. T2 of the satellite transition shows a minimum around 75 K and a rapid decrease below 140 K, in spite that T2 of the central transition changes gradually. Since T1 shows monotonous dependence on temperature for both transitions below 140 K, the anomaly of T2 cannot be caused by the fluctuation of the local magnetic field. Some lattice dynamics which reveal coherence only among the satellite transitions, such as an alternation of the electrical field gradient, may be an origin of those behaviors.