Systematic Survey of the alpha-alpha Interaction

A systematic survey of the subject of the $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\alpha}$ interaction is made. The early observations of $\ensuremath{\alpha}$ emission and resulting theoretical descriptions, especially the $\ensuremath{\alpha}$-particle model of nuclei, are described, as are more recent $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\alpha}$ scattering experiments. The latter were designed to obtain information about the nature of the $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\alpha}$ interaction and about the energy levels of $^{8}\mathrm{Be}$ by studying the resonance behavior of the phase shifts. The phenomenological approach, i.e., the attempt to construct the $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\alpha}$ potential which reproduces the experimental phase shifts, is described as are detailed theoretical constructions of the repulsive inner part and attactive outer part of the $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\alpha}$ interaction. Studies of how the $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\alpha}$ interaction provides better understanding of the structure of $\ensuremath{\alpha}$-clustered nuclei and also of the fundamental forces between the constituents of these nuclei are discussed. Suggestions for the direction of further efforts are made.