K = 0 + bands in Gadolinium nuclei
The recent 160Gd(p,t) 158Gd experiment has raised again the question about the nature of the low-lying excited 0 + states in deformed nuclei. New (p,t) experiments have resolved typically about ten low-lying excited 0 + states. Calculations using the IBA model, the projected shell model and the quasiparticle-phonon model have answered partially this question and showed the complicated nature of these states. We study the energy levels, their wave function content, and the corresponding B(E2) transitions in 156,158,160Gd nuclei, in the framework of the pseudo-SU(3) model. The theory uses a realistic Hamiltonian with single-particle energies and monopole pairing interactions in addition to the usual quadrupole-quadrupole term, with the pairing and quadrupole-quadrupole strengths taken from systematics. The calculations are carried out with a set of basis states with pseudo-spin zero proton and neutron configurations. The calculated B(E2) values suggest that the first excited 0 + state might have a mixed rotational and collective vibrational character, where the latter - quasiparticle type excitations - are not considered in this calculation. © 2006 American Institute of Physics.