Nuclear shape transition between the limiting symmetries U(5) and SU(3) of interacting boson model applied to double even Hafnium isotopic chain

摘要

The shape structure of even-even Hafnium isotopic chain Hf160-180 is investigated within the framework of sd-version of interacting boson model (IBM1) using coherent state formalism, the Hamiltonian operator of the model contains Casimir operators of the dynamical symmetries U(5) and SU(3) of the IBM1 besides the Casimir operator of the subgroup 0(3). The potential energy surfaces (PES's) are calculated by diagonalizing the Hamiltonian between the coherent states. The PES's are analyzed in terms of the shape variables beta, gamma and the essential parameters r(1), r(2) and the locus of the critical points are identified. The model parameters for each nucleus are adjusted so as to reproduce some selected low lying energy levels and reduced electric quadrupole transition probabilities B(E2) with corresponding experimental data.