J. Pelzl et al., EFFECT OF DEUTERON SUBSTITUTION ON STRUCTURAL PHASE-TRANSITION IN (NH4)(2)MCL6, Journal of the Korean Physical Society, 32, 1998, pp. 87-90
Substitution of hydrogen by deuterium induces additional phase transit
ions in some ammonium hexahalometallates below 77 K. For the first tim
e such an isotope effect was investigated in partially and completely
deuterated (NH4)(2)MCl6 (M=Te, Se) using Raman studies, CI-NQR and die
lectric measurements. The deuteration effect observed in the tellurium
salt has been explained by the slowing down of deuteron motion in a t
riangular shaped potential around the threefold axis and related suppl
ementary movements of the octahedra.