The magnetic-dipole and electric-quadrupole hyperfine-interaction constants of the ground state of 2.3-h ${}_{}{}^{165}{}_{}{}^{}\mathrm{Dy}$ have been measured to be $a=\pm 89.8\pm 0.7$ MHz and $b=\mp 1521\pm 30$ MHz, respectively. From these data we calculate $\mu =-0.50\mathrm{}$ nm and $Q=2.8\mathrm{}$ b, uncorrected.

• Received 7 August 1967

DOI:https://doi.org/10.1103/PhysRev.165.1360