Microscopic description of structural evolution in Pd, Xe, Ba, Nd, Sm, Gd and Dy isotopes

Abstract

Aiming to understand the role of triaxiality and the evolution of the ground state nuclear shapes, we have carried out a microscopic study for a series of chains of Pd, Xe, Ba, Nd, Sm, Gd, and Dy isotopes. This is done within the self-consistent Relativistic–Hartree–Bogoliubov (RHB) formalism, and supported by the Triaxial Projected Shell Model (TPSM) approach. Pairing interaction separable in the momentum space with DD-ME2 force parameter is used to generate the potential energy surfaces (PESs) under the axial and triaxial symmetry. Shape evolution manifest themself in very clear manner in almost all the isotopic chains. Properties of the global mimima have been found to be in good agreement with the available experimental data. Relatively flat PESs, and γ-soft nature, have been suggested 108,110Pd, 132,134Xe and 134Ba as good candidates for E(5) symmetry, while 102Pd is not found suitable for E(5) symmetry. The PESs with a bump, and rigidity against triaxial variable (γ) suggested 150Nd, 152Sm and 154Gd to be good candidates while 150Sm and 156Dy are poor candidates of X(5) critical-point symmetry. The findings of the present RHB calculations supported by TPSM are qualitatively in good agreement with the experimental and other theoretical calculations.