Shape Coexistence at the Outer Edges of Stability

A major program of Gammasphere when coupled with the Fragment Mass Analyzer (FMA) has been to study excited states in nuclei beyond the proton drip line. We have recently performed in-beam experiments using Gammasphere + FMA to measure excited states in proton rich Au, Hg, Tl and Pb isotopes. These studies have allowed us to characterize the evolution of nuclear shapes as one approaches the proton drip line. In two of the isotopes studied, namely 175Au and 179Hg, structures built on three distinct shapes have been found to coexist at low excitation energy.