Extended interacting boson model with configuration mixing description for ${}_{98}\mathrm{Mo}$

An extended version of the interacting boson model (IBM), encompassing two-particle–two-hole (2p-2h) excitations originating from below a valence shell and one-particle–one-hole (1p-1h) excitations extending to the upper next-nearest major shell, is developed to investigate cross-shell excitation effects in the transitional nucleus ${}_{98}\mathrm{Mo}$. This extended IBM framework is utilized to reproduce experimentally observed properties such as low-lying positive-parity level energies, $B\left(E2\right)$ values, and the electric quadrupole moment of the $2_1^{+}$ state, ${\rho }^2(E0,0_2^{+}\to 0_g^{+})$, as well as the strength functions of the isoscalar giant monopole resonance (ISGMR) and the isoscalar giant quadrupole resonance (ISGQR) in ${}_{98}\mathrm{Mo}$. It is shown that the extended consistent-$Q$ IBM, incorporating configuration mixing of both 2p-2h excitations from below the valence shell and 1p-1h excitations to the upper next-nearest major shell, describes the low-lying structural properties and the ISGMR and ISGQR strength distributions of ${}_{98}\mathrm{Mo}$ quite well, with the ISGMR and the ISGQR strength distributions comparable to the results of the self-consistent quasiparticle random-phase approximation with Skyrme interactions.