THE EVOLUTION OF NUCLEAR-STRUCTURE - THE NPNN SCHEME AND RELATED CORRELATIONS

The evolution of collective nuclear structure is discussed from a hori zontal perspective, that is, as a function of the number of valence pr otons and neutrons. Starting from an explicit recognition of the impor tance of the valence residual p-n interaction in the equilibrium shape and structure of nuclei, the phenomenological NpNn scheme is presente d, and validated via an analysis of empirical p-n interaction strength s. Applications of the NpNn scheme are presented which exploit this pa radigm of structural evolution. The physics underlying occasional devi ations from the NpNn scheme is extracted and new signatures of structu re and of nuclear shape components are developed which will be useful for the study of exotic nuclei with radioactive beams. Finally, the sm ooth correlations of many observables with NpNn leads to a study of th e correlations between different collective observables themselves. Th e remarkable results stemming from this approach are summarized.