Barrier distributions as a tool to investigate fusion and fission

The recent availability of precisely measured fusion cross-sections has enabled the extraction of a representation of the distribution of barriers encountered during fusion. These representations, obtained from a variety of reactions, provide a direct observation of how the structure of the fusing nuclei changes the inter-nuclear potential landscape, thus affecting the fusion probability. Recent experiments showing the effects of static quadrupole and hexadecapole deformation, single- and double-phonon states, transfer of nucleons between two nuclei, and high-lying excited states are reviewed. The application of these concepts to the explanation of the anomalous fission-fragment anisotropies observed following reactions with actinides is discussed.