Quadrupole Effect on NMR Line Shape in Strained Gold Metal

Abstract

The second-order effect of the quadrupole interaction on the shape of the central line in strained crystals has been investigated on the basis of an analysis of the experimental spin-echo share. With the Gaussian distribution for random field gradients, the following results were obtained: (i) Line shares are similar to the one in the absence of field gradient. When the quadrupole interaction is increased from zero, the line shape is broadened to be observable, and tends to a definite limit rather than to the one with infinite half-width. From the experimental condition, the perturbation treatment is seen to be valid for line shapes near the limit. (ii) The line shape becomes asymmetric. (iii) The resonance-line shift due to the quadrupole interaction is negligibly small in comparison with the observed one. (iv) The asymmetry in field gradients may be neglected for the line shape.