Collective structure of the even-mass Pd isotopes

A collective model which incorporates vibrations and rotations of a permanently deformed nucleus is applied to ${}_{}{}^{102}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{104}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{106}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{108}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{110}{}_{}{}^{}\mathrm{Pd}$, ${}_{}{}^{112}{}_{}{}^{}\mathrm{Pd}$, and ${}_{}{}^{114}{}_{}{}^{}\mathrm{Pd}$. Theoretical energy levels are compared with those from experiment and remarkably good agreement is found. The model wave functions are further tested via $B\left(E2\right)$ ratios and agreement with experiment is very good. An unidentified extra degree of freedom is treated essentially by ansatz but a discussion of the possible origin of that degree of freedom is given. Trends in the model parameters are shown and the conclusion drawn that to a good approximation the states of these even-mass Pd isotopes are well described as those of collective rotations and vibrations.