A survey of alpha-clustering

The concept of alpha-clustering has found many applications to nuclear reactions and nuclear structure. Calculations of the properties of nuclear matter indicate that condensation into alpha-particles occurs when the density is somewhat less than the central nuclear density, suggesting that alpha clustering is favoured in the nuclear surface. This provides an explanation of alpha-decay which is now quantitatively successful. The concept of the alpha-particle mean field is now widely used to unify the alpha-particle bound and unbound states found by alpha-transfer reactions, and the scattering of alpha-particles by nuclei. The analysis of the structure of 44Ti using the alpha-40Ca potential has been particularly successful. There are now several phenomenological alpha-alpha interactions that fit the low-energy phase shifts, and these are used to calculate the structure of light nuclei, particularly those composed of 2N protons and 2N neutrons. Many excited states of such nuclei can be studied in this way, and a particularly interesting class of states is those composed of a linear chain of alpha-particles, some of which have been identified experimentally.