Proton Spin–Lattice Relaxation in Hexagonal Ice

Abstract
The results of measurements of the proton spin–lattice relaxation time T 1 in ice are reported. The ice samples were single crystalsgrown by zone refining at atmospheric pressure. The measuredactivation energy for the T 1 process is 14.1 ± 0.1 kcal/mole. No anisotropy of T 1 is observed. A theoretical calculation of T 1 is presented, from which molecular displacement times are deduced.