Nuclear shape coexistence: A study of the even-even Hg isotopes using the interacting boson model with configuration mixing

Background: The Po, Pb, Hg, and Pt region is known for the presence of coexisting structures that correspond to different particle-hole configurations in the shell model language or equivalently to nuclear shapes with different deformation.Purpose: We intend to study the configuration mixing phenomenon in the Hg isotopes and to understand how different observables are influenced by it.Method: We study in detail a long chain of mercury isotopes, ¹⁷²⁻⁻²⁰⁰Hg, using the interacting boson model with configuration mixing. The parameters of the Hamiltonians are fixed through a least-squares fit to the known energies and absolute $B(E2)$ transition rates of states up to 3 MeV.Results: We obtained the IBM-CM Hamiltonians and we calculate excitation energies, $B(E2)$'s, quadrupole shape invariants, wave functions, isotopic shifts, and mean-field energy surfaces.Conclusions: We obtain a fairly good agreement with the experimental data for all the studied observables and we conclude that the Hamiltonian and the states we obtain constitute a good approximation to the Hg isotopes.