Abstract
A study of the ground states of the laser-ionized and mass-separated odd-odd isotopes( 180,182)Au was performed using the Resonance Ionization Laser Ion Source, Windmill detection setup and ISOLTRAP Multi-Reflection Time-of-Flight Mass Spectrometer at ISOLDE, CERN. A complex fine-structure alpha-decay pattern of Au-180 was deduced, providing insight into the low-lying levels in the daughter nucleus Ir-176. An alpha-decay branching ratio of b(alpha)(Au-180) = 0.58(10)% and a half-life of T-1/2 = 7.2(5) s have also been derived, allowing for the calculation of the reduced alpha-decay widths and determining the degree of hindrance of respective alpha-decay branches. From complementary first in-source laser spectroscopy measurements of the hyperfine structure in atomic transitions of Au-180,Au-182 , the nuclear magnetic moments of mu(Au-180) = -0.83(9) mu(N) and mu(Au-182) = 1.66(9) mu(N) were extracted with an inclusion of a correction for the hyperfine anomaly. Based on the observed hyperfine structure patterns, and on the comparison of the measured and calculated p. values, a preferred ground-state spin and parity I-pi(Au-180(gs)) = (1+) is proposed, and the earlier assignment of I-pi(Au-182(gs)) = (2+) is confirmed. For Au-180, the most probable proton-neutron Nilsson configuration of pi/3/2(-)[532] circle times nu 5/2(-)[512] suggests the same proton state as in the heavier deformed odd-odd nuclei Au-182,Au-184.