Nuclear Magnetic Relaxation in NaCl at High Temperatures

Measurements of $T_1$ and $T_2$, the spin-lattice and spin-spin relaxation times, are reported for ${\mathrm{Na}}^{23}$ and ${\mathrm{Cl}}^{35}$ nuclei in NaCl from room temperature to the melting point. For single-crystal samples below 700°K, $T_1$ is due to quadrupolar interactions of the nuclei with lattice vibrations and diffusing vacancies, and $T_2$ arises from the dipolar interaction between nuclei. A jump frequency for positive ion vacancy motion of 4×${10}^7$ ${\sec }^{-1\mathrm{}}$ at 510°K is obtained, in good agreement with conductivity measurements. At higher temperatures a number of anomalous features appear and possible explanations are discussed.