A calculation of the position of the quasi-β and quasi-γ bands for the transitional nucleus 154Dy with Monte Carlo methods

A calculation of the excitation energy of the 0+ states and of the 2+ states is performed using Monte Carlo methods for the nucleus 154Dy. The Hamiltonian is assumed to be a monopole+quadrupole pairing+quadrupole with the parameters fixed by the spectroscopic Monte Carlo method so as to reproduce the experimental excitation energies of the yrast states up to J 8 within the 50-82 and 82-126 proton and neutron major shells. The resulting Hamiltonian has been diagonalized in the J = 0 and J = 2 subspaces using the quantum Monte Carlo method. The size of the basis is fixed by comparing the yrast energies obtained with the basis-independent spectroscopic Monte Carlo method, and those obtained with the quantum Monte Carlo method. The excitation energy of the 0+2 is much higher than the experimental value. The structure of the 0+2,3 and of the 2+2,3 eigenstates is discussed in terms of fluctuating intrinsic states and resolved in terms of the deformation variables. (brief report)