Shell model description of normal parity bands in even-even heavy deformed nuclei

G. Popa, Louisiana State University
J. G. Hirsch, Instituto de Ciencias Nucleares de la UNAM
J. P. Draayer, Louisiana State University


The pseudo-SU(3) model is used to describe the low-energy spectra and electromagnetic transition strengths in 156Gd, 158Gd, and 160Gd. The Hamiltonian includes spherical single-particle energies, the quadrupole-quadrupole interaction, proton and neutron pairing interactions, plus four rotorlike terms. The quadrupole-quadrupole and pairing interaction strengths are assigned the values χ=23/A-5/3 and Gπ = 21/A, Gv = 17/A, respectively. The single-particle energies were taken from experiment but scaled to yield an overall best fit. For the other four rotorlike terms, which do not mix SU(3) representations and induce only small changes in the spectra, a consistent set of parameters is given. The basis states are built as linear combinations of SU(3) states which are the direct product of SU(3) proton and neutron states with pseudospin zero. The results are in good agreement with experimental data, demonstrating the suitability of the model to describe heavy deformed nuclei.