Evolving shapes of nuclei via evolutionary algorithm: Dynamics of the shape of 25Al nucleus in single-particle states

Abstract

We present a new approach that enables us to extract shapes of the self-consistent field of a nucleus in the ground and single-particle excited states directly from the experimental data on the energies, spins, and parities of these states, as well as the measured probabilities of electromagnetic transitions between them. The approach is based on the use of an evolutionary algorithm and a series of trigonometric functions that simulates the shape of a nucleus. With help of this approach we show that the 25Al nucleus is differently deformed in its single-particle states and the contribution of the hexadecapole deformation is not small compared to the contribution of the quadrupole deformation. Our approach indicates that the abnormally weakly deformed ground state of the 25Al nucleus is a shape phase transition point from the spherical state of the nucleus into a deformed state.