Shapes and stability within the interacting boson model: effective Hamiltonians

Abstract

For even-even isotope and isotone nuclei described by the interacting boson model a geometric description is found. This geometric interpretation is made in the essential parameter space determined by the catastrophe theorly. The energy surfaces associated to the effective IBA Hamiltonian for the Ru, Ba, Sm, Cd, Os, Pt, and U isotopes anti given, together with those of the isotones N = 88 and N = 90. Shape phase transitions of these chains of nuclei are set by the separatrix and its order is compared with the experimental two nucleon separation energies.