Hyperfine structure and nuclear moments of 161Er and 163Er

The hyparfine interaction constants in the atomic ground state of 161Er and 163Er have been measured using the atomic-beam magnetic resonance method. The results are, for 161Er: = −183.8(1.4) MHz, b = −1738(10) MHz, and for 163Er: a = 167(7) MHz, b = −3275(130) MHz. The nuclear moments are evaluated by comparison with 167Er. The resulting moments are, for 161Er: μI = −0.369(5) n.m., Q = 1.20(9) b, and for 163Er: μI = 0.56(3) n.m., Q = 2.2(2) b. The dipole moments are corrected for diamagnetic shielding and the uncertainties in the quadrupole moments include the error introduced by the Sternheimer effect.