Collectivity of neutron-rich palladium isotopes and the valence proton symmetry

Abstract

Absolute transition probabilities for the first ${2}^{+}$ states in $^{110,114}\mathrm{Pd}$ were measured using the recoil distance Doppler shift technique following projectile Coulomb excitation at intermediate beam energy. This technique was applied for the first time to projectiles produced in a primary fragmentation reaction, which get Coulomb excited in a secondary reaction. The $^{110}\mathrm{Pd}$ data was used to check the novel experimental technique as well as the data analysis procedure, which is based on the examination of $\ensuremath{\gamma}$-ray line shapes. Whereas the measured $B(E2)$ value for $^{110}\mathrm{Pd}$ agrees very well with the literature, the value obtained for $^{114}\mathrm{Pd}$ differs considerably. The new experimental data are compared to calculations in the framework of the Interacting Boson Model. The data are also used to test the novel concept of valence proton symmetry, which allows for extrapolation of nuclear properties to very neutron-rich nuclei.