UNIFIED DESCRIPTION OF COLLECTIVE NUCLEI WITH THE INTERACTING BOSON MODEL

It was recently demonstrated that the empirical linear correlation of E(4(1)(+)) with E(2(1)(+)) is reproduced by the interacting boson mode l 1 (IBA-1) if a constant value for the coefficient kappa of the Q . Q term is used. This constancy motivates the present investigation of w hether it is possible to find sets of IBA-1 parameters, with fixed kap pa, that reproduce the data for a more general set of observables and a wide range of nuclei. A consistent procedure, based on contour plots of key observables, was used to extract epsilon and chi values for 14 5 nuclei spanning the Z = 50-82 shell, which give reasonable overall a greement with the data with smoothly varying parameters. The constant kappa constraint sometimes leads to parameter values different than no rmal: finite epsilon values (similar to 0.1 MeV) even for rotational n uclei and large chi values for transitional and vibrational nuclei tha t even increase towards the vibrational region. Finally, a systematic correlation of epsilon values with E(2(1)(+)) was found.