REORIENTATIONAL MOTION OF THE OH-ION IN CUBIC SODIUM-HYDROXIDE

The rotational motion of the OH- ion was studied in cubic NaOH at 575 K with quasielastic incoherent neutron scattering. The data are compared to two simple models yielding values for the radius of rotation R, the translational mean square displacement 〈u2〉H, the rotational jump rate τ-1 and the rotational diffusion coefficient DR. The following parameter values are obtained: (a) rotational jump model: R = 0.95 A ̊, 〈u2〉H = 0.052 A ̊2, τ-1 = 2 meV, (b) rotational diffusion model: R = 0.99 A ̊, 〈u2〉H = 0.046 A ̊2, DR = 0.72 meV. © 1979.