Low-lying spectra and E2 transition rates in even-even Pd isotopes in the interacting boson model

The positive parity collective states in the even-even (100)Pd-(116)Pd isotopes are studied in the framework of the interacting boson model. A schematic Hamiltonian capable of describing their spectra and transition is used. It is found that the spectra can be well described by a U(5) plus SU(3) perturbation interaction. As the valence neutron number changes, the structure of the isotopes shows regular patterns of change. In the meantime, the behaviour of O(2)(+) can also be partially described by the model.