NMR ANISOTROPY IN IRRADIATED LITHIUM HYDRIDE.

Abstract Lithium hydride single crystals irradiated with 60Co gamma rays show a motionally narrowed hydrogen signal to pulsed NMR measurements. The transverse relaxation time of this signal shows a marked angular dependence as an oriented crystal is rotated relative to the magnetic field. This orientation effect is considered to be due to wall relaxation of hydrogen gas in cubic bubbles. That portion of the transverse relaxation time caused by wall interactions is shown to be proportional to the dipolar relation (1–3 cos2 α)−1, where α is the laboratory angle of rotation. The longitudinal relaxation time is not affected by crystal rotation.