Nuclear ground-state spin of $^{185}$Au and magnetic moments of $^{187, 188}$Au: Further evidence for coexisting nuclear shapes in this mass region

Hyperfine structure measurements have been performed in some neutron- deficient gold isotopes, using online atomic-beam magnetic resonance (ABMR) techniques at the ISOLDE facility, CERN. The following results have been obtained: /sup 185/Au, I=/sup 5///sub 2/; /sup 187/Au, Delta nu =44.35(60) GHz, mu =0.72(7) nm and /sup 188/Au, Delta nu =+or-2992 (30) MHz. The influence of the hyperfine anomaly was discussed. With due regard to this effect, the magnetic moments of /sup 188/Au may be given as mu =+or-0.07(3) nm. The experimental data were compared with the results from calculations based on the particle-asymmetric rotor model. Strong evidence for coexisting nuclear shapes in /sup 185/Au and for a much larger ground-state deformation in /sup 185/Au than in /sup 187/Au was presented. (43 refs).