SYSTEMATIC STUDY OF SUBBARRIER FUSION IN RARE-EARTH NUCLEI

The recent accurate measurements of fusion cross sections at subbarrie r energies have enabled extraction of barrier distributions which coul d provide a novel test for collective models. We carry out a systemati c study of subbarrier fusion in rare-earth nuclei using a scheme which incorporates the interacting boson model for nuclear structure effect s. The existing data on vibrational and rotational nuclei are fitted w ith a consistent set of parameters which are then used to predict the fusion cross sections and distribution of barriers in transitional nuc lei. Contrary to vibrational and rotational nuclei where the cross sec tions increase smoothly with increasing deformation or mass number, tr ansitional nuclei exhibit sharp changes in the barrier distribution du e to shape-phase transitions. An accurate measurement of fusion cross sections for Pt and Os nuclei could thus provide a sensitive test for competing models in this region.