An investigation of the structure of the nuclear surface

Abstract

In a group of alpha-decay transuranic elements the structure of the nuclear surface has been investigated. Firstly, in the case of a short-cut-off potential it is shown that, by using a single-particle alpha wave function describing a `smooth' surface and by calculating the absolute emission rate, the ratio between the experimental and calculated values is a factor of about four-figure magnitude. If we assume that alpha particles do exist in the nuclear surface and if we take into consideration the alpha correlations, the difference between the calculated data and the experimental decay rate decreases to a significant degree; therefore it is very likely that the pre-existence of the quasi-alpha particles causes the roughness of the nuclear structure. Next, in the case of the Coulomb plus the Igo potential, the ratio of the experimental to the calculated value of the absolute emission rates differs by a factor of about 10 without and with alpha correlations. The role of alpha correlations is to bring the barrier nearer to the nucleus, thus smoothing the `rough' nuclear surface. The alpha barrier begins at 8.18 fm, which is in good agreement with the inflection point of the theoretical alpha probability functions at 8 25 fm found by Mang and Rasmussen.