Nuclear magnetic double resonance has been used to investigate first-order electric quadrupole interactions of ${\mathrm{Na}}^{23}$ and ${\mathrm{Cl}}^{35}$ nuclei near an Ag ion substituted for Na in NaCl. The study has determined the direction of the principal axes, asymmetry parameter $\eta$, and strength of the interaction $e^2\mathrm{Qq}$ for sodium ions at a (2, 0, 0) position, and chlorine ions at (2, 1, 0) position relative to the impurity at (0, 0, 0).

• Received 18 August 1967

DOI:https://doi.org/10.1103/PhysRev.166.350