Description of some chains of isotopes and isotones in the interacting-boson approximation

The effective IBA hamiltonian is used to describe the low-lying spectra and electromagnetic properties of several series of even-even chains of isotopes and isotones. Applications are made to the Sm, U, Pt, Os and Ru chains of isotopes and to the following chains of isotones: ISO88 that includes 144056Ba, 146058Ce, 148060Nd, 150062Sm, 152064Gd, 154066Dy, 156068Er and 158070Yb, and the ISO90 composed of 146056Ba, 148058Ce, 150060Nd, 152062Sm, 154064Gd, 156066Dy, 158068Er and 160070Yb. For all the members of each chain, only one set of parameters of the effective hamiltonian is calculated by a least-squares analysis, making this a global study instead of a nucleus-by-nucleus zone. The model thus applied reproduces some 250 experimental energies with a r.m.s. deviation of about 100 keV. Electromagnetic transitions B(E2) are also calculated globally for each chain by fitting the experimental data of several types of transitions. ((orig.))