Interacting boson approximation-2 analysis of the Pd and Ru chains. I. Mixed symmetry states ofFmax−1character in even palladium isotopes

Abstract

An analysis of positive parity levels in the even palladium isotopes ${}^{100\ensuremath{-}116}$Pd has been carried out in the framework of the interacting boson approximation-2 model to identify states having large mixed-symmetry components. By means of numerical calculations, performed in the U(5) limit of the model, it has been possible to find simple relations obeyed by the eigenvalues of the generalized Majorana operator for the mixed-symmetry states having ${F=F}_{\mathrm{max}}\ensuremath{-}1.$ These results have been utilized as a starting point for our analysis. Experimental energies, static and transition electric quadrupole and magnetic dipole moments as well as mixing ratios and intensity ratios have been compared to the values calculated by using a realistic Hamiltonian. In the analysis only six out of the twelve model parameters have been varied as a function of the neutron number. A good overall agreement has been found. A detailed investigation of the level structure made it possible to identify whole groups of states of predominant mixed-symmetry character and to establish, in most cases, a close correspondence with states of the U(5) limit of the model.