Shape coexistence in ¹⁸⁷Au

The level structure of odd-proton ¹⁸⁷Au was studied using the ¹⁷²Yb(¹⁹F,4n) reaction. Gamma-gamma coincidence, angular distributions and γ-γ-time measurements were used to establish the energies, spins, parities, and lifetimes for the states in the decay scheme of ¹⁸⁷Au. Both prolate and oblate structures have been established. The prolate bands are built on the πh_9/2 (α=±(1/2) and the πi_13/2 (α=(1/2) particle states. An oblate, strongly coupled band built on a 90±10 ns isomeric state is reported for the first time. A second oblate structure built on the h_11/2 proton-hole state was established to much higher spin than before. The backbend present in the πi_13/2 band has been interpreted as the alignment of a pair of h_9/2 protons.