Knight shift ofCd111impurities in liquid selenium

The Knight shift of dilute ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}$ dopants in liquid selenium has been measured at ∼800 °C by the gamma-gamma perturbed angular-correlation method. The Knight shift is found to be zero with an uncertainty of 0.5%. This result indicates that magnetic hyperfine exchange with paramagnetic dangling bonds is not the dominant mechanism for nuclear relaxation of ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}$. Instead, ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}$ relaxation in chalcogenide liquids must be attributed to the interaction of the nuclear quadrupole moment with fluctuating electric field gradients.