Hyperfine structure and nuclear moments of 166Tm

Abstract

The hyperfine structure of the 4 f 136 s 2, 2F 7 2 ground state of 166Tm has been studied using the atomic-beam magnetic resonance method. The hyperfine interaction constants and inferred nuclear moments are: |a| = 37.1 (5) MHz, |b| = 2935(40) MHz, b a < 0, μ I = 0.092(2) n.m., Q = 1.85(15) b . The nuclear moments are calculated from the hyperfine interaction constants using the 〈r −3〉 value of the 4f electrons obtained from the measured magnetic dipole constant and moment of 169Tm. The signs of the nuclear moments of 166Tm are suggested by the positive value of Q/ μ I combined with the positive values of Q in this region of strong nuclear deformation. The magnetic dipole moment is corrected for diamagnetism, and the electric quadrupole moment for the Sternheimer effect. The experimental results are compared with predictions made on the basis of the Nilsson model.