²H NMR Line Shapes and Spin−Lattice Relaxation in Ba(ClO₃)₂·²H₂O

Solid-state deuterium NMR measurements were used to characterize the flipping motion of the water molecule in barium chlorate monohydrate, Ba(ClO 3 ) 2 · 2 H 2 O. In particular, temperature-dependent quadrupole echo line shapes, their τ dependence and spectral intensities, and the anisotropy of the spin−lattice relaxation observed in inversion recovery experiments permit measurement of the 2-fold flipping rates. These were studied as a function of temperature and yield an activation energy E a = 30 kJ/mol and pre-exponential factor A 0 = 1.5 × 10 14, which are typical for molecular motion constrained by hydrogen bonds of moderate strength. A discussion of experimental considerations is also presented.