Description of the Shape Coexistence in ⁹⁸Mo with IBM2

We investigate the properties of the low-lying states and the relevant shape dynamics of ⁹⁸Mo within the framework of the proton-neutron interacting boson model (IBM2). By considering the relative energy of the d proton boson to be different from that of the neutron bosons, the low-lying levels and the key observable B(E2) transition branching ratios are calculated. The characteristic feature of the energy spectrum and the most crucial available structure indicator indicate that the substantial mixing between the spherical-vibrational and γ-unstable shapes in ⁹⁸Mo. The calculation results of the overall deformation in ⁹⁸Mo are almost the same for both the ground and the first excited 0⁺ states, showing a weak deformation. While the triaxiality parameter indicates that the mostly triaxial shape with some oblate for the ground state, and the triaxial shape with some prolate for the excited 0⁺₂ state, being equilibrium shapes of spherical-vibrational and γ-unstable in ⁹⁸Mo.