Nuclear Matter

Abstract

Dimensions of nuclei and the density distribution inside nuclei. The spatial structure of atomic nuclei, which are composite particles consisting of simpler particles, namely, neutrons and protons, is determined by the spatial structure of the neutrons and protons and by the nature of the interaction between them. As we have already mentioned, a distinguishing feature of nuclei is the fact that they have sharply defined boundaries. Since the nuclear interaction between nucleons is much stronger than the Coulomb interaction, the dimensions of nuclei and the distribution of the nucleons inside them are mainly determined by the nuclear forces. Because of the charge independence of the nuclear forces, the spatial distributions of neutrons and protons inside nuclei are almost identical. A certain increase of the volume occupied by the protons, due to the Coulomb repulsion, is matched by approximately the same increase of the volume occupied by the neutrons, arising from the increase in the number of excess neutrons with increasing nuclear charge. Therefore, it is usually assumed that the dimensions of the nucleus are determined with very good accuracy by the distribution of the charge density.