Nuclear ground-state spin of185Au and magnetic moments of 187, 188Au: Further evidence for coexisting nuclear shapes in this mass region

Hyperfine structure measurements have been performed in some neutron-deficient gold isotopes, using on-line atomic-beam magnetic resonance (ABMR) techniques at the ISOLDE facility, CERN. The following results have been obtained: ¹⁸⁵Au, I = $\text{5}\text{2}$; ¹⁸⁷Au, Δv = 44.35(60) GHz, μ = 0.72(7) n.m. and ¹⁸⁸Au, Δv = ± 2992(30) MHz. A discussion of the influence of the hyperfine anomaly is included. With due regard to this effect, the magnetic moments of ¹⁸⁸Au may be given as μ = ± 0.07(3) n.m. The experimental data are compared with the results from calculations based on the particle-asymmetric rotor model. Strong evidence for coexisting nuclear shapes in ¹⁸⁵Au and for a much larger ground-state deformation in ¹⁸⁵Au than in ¹⁸⁷Au is presented.