Charge and transition densities of samarium isotopes in the interacting boson modei

The interacting boson approximation (IBA) model has been used to interpret the ground-state charge distributions and lowest 2⁺ transition charge densities of the even samarium isotopes for A = 144-154. Phenomenological boson transition densities associated with the nucleons comprising the s- and d-bosons of the IBA were determined via a least squares fit analysis of charge and transition densities in the Sm isotopes. The application of these boson transition densities to higher excited 0⁺ and 2⁺ states of Sm, and to 0⁺ and 2⁺ transitions in neighboring nuclei, such as Nd and Gd, is described. IBA predictions for the transition densities of the three lowest 2⁺ levels of ¹⁵⁴Gd are given and compared to theoretical transition densities based on Hartree-Fock calculations. The deduced quadrupole boson transition densities are in fair agreement with densities derived previously from ¹⁵⁰Nd data. It is also shown how certain moments of the best fit boson transition densities can simply and successfully describe rms radii, isomer shifts, B(E2) strengths, and transition radii for the Sm isotopes.