High-Spin States in Au-179: Spectroscopy of Shape-Driving Orbitals Beyond the Neutron Midshell

Multiple band structures in Au-179 are established from gamma-ray spectroscopic measurements with Gammasphere at the Argonne Fragment Mass Analyzer. The yrast band, based on the 13/2(+) proton, confirms the predicted drop in excitation energy of the prolate deformed band head as compared to the heavier isotopes. The implications for the prolate energy minimum in odd-mass Au nuclei beyond the neutron i(13/2) midshell (N<102) are discussed.