A calculation of the position of the quasi-beta and quasi-gamma bands for the transitional nucleus Dy-154 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 Dy-154. 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.