A systematic search of the shape phase transitions and isotopic shift of the neutron-rich barium (Ba; [Formula: see text]) isotopes, as a candidate for transitional nuclei, is done within the covariant density functional theory (CDFT). The relativistic Hartree–Bogoliubov (RHB) formalism with separable pairing and relativistic mean-field (RMF) with BCS pairing are used. The constraint calculations assuming the axial symmetry as well as triaxial symmetry clearly manifest the shape coexistence and the transitional behavior in these nuclei. A strong shell closure is observed at [Formula: see text] and weaker shell/subshell closure is observed at [Formula: see text]. Shape transition below and above the shell closure location at [Formula: see text] (from prolate to spherical to prolate) is there. The candidates for [Formula: see text] and [Formula: see text] dynamical symmetries are found to be [Formula: see text]Ba, [Formula: see text]Ba and [Formula: see text]Ba, [Formula: see text]Ba nuclei, respectively. The calculated results are compared with the available experimental data and are in good agreement. We have investigated the model dependence as well as dependence on various model parameters. A comparison is made with other theoretical models: infinite nuclear matter (INM) model, macro–microscopic finite-range droplet model (FRDM) and the self-consistent Hartree–Fock–Bogoliubov (HFB) model. Overall good agreement is found within the different models used and between the calculated and experimental results.
Coarse-grained density functional theory of order-disorder phase transitions in metallic alloys
