Masses and Radii of the Nuclei with N>=Z in an Alpha-Cluster Model

TL;DR

This paper presents an alpha-cluster model to analyze nuclear masses and radii, revealing how the number of alpha-clusters and excess neutrons relate to nuclear stability and structure.

Contribution

It introduces a model combining a core and surface molecule to explain nuclear properties and determines a specific density value that accounts for excess neutrons in stable nuclei.

Findings

Number of alpha-clusters decreases with increasing A for isotopes of fixed Z.

Core binding energy density reaches saturation at 2.55 MeV/fm^3.

The model explains the specific number of excess neutrons in stable nuclei.

Abstract

In the framework of a recently developed alpha-cluster model a nucleus is represented as a core (alpha-cluster liquid drop with dissolved excess neutron pairs in it) and a nuclear molecule on its surface. From analysis of experimental nuclear binding energies one can find the number of alpha-clusters in the molecule and calculate the nuclear charge radii. It was shown that for isotopes of one Z with growing A the number of alpha-clusters in the molecule decreases to three, which corresponds to the nucleus 12C for even Z and 15N for odd Z, and the specific density of the core binding energy \rho grows and reaches its saturation value. In this paper it is shown that the value \rho=2.55 MeV/fm^3 explains the particular number of excess neutrons in stable nuclei.