DYNAMICS OF A GLYCINE MOLECULE IN A NEW FERROELECTRIC GLYCINE PHOSPHITE STUDIED BY PROTON NMR

The second moments of the proton magnetic resonance lines and relaxati on times in the laboratory frame T-1, in polycrystalline glycinum phos phite (NH(3)(+)CH(2)COOJ)(H2PO3-) were measured. The proton spin-latti ce relaxation measurements reveal one minimum due to the C-3 reorienta tions of the amino groups of glycinum cations. Analysis of the relaxat ion data yields the activation energy barrier of 28.7 kJ mol(-1). Seco nd moment measurements confirm the phase transition at T-c = 224 K kno wn from different studies. The molecular mechanism of the order-disord er phase transition is discussed. (C) 1998 Published by Elsevier Scien ce Ltd.