RT Journal Article T1 At the borderline of shape coexistence: Mo and Ru A1 Maya Barbecho, Esperanza A1 Baid, Samira A1 Arias, José Miguel A1 García Ramos, José Enrique K1 Shape coexistence, Mo, Ru, Interacting Boson Model AB Background: Even-even isotopes of Mo (Z = 42) and Ru (Z = 44) are nuclei close to the subshell closure at Z = 40, where shape coexistence plays a significant role. As a result, their spectroscopic properties are expected to resemble those of Sr (Z = 38) and Zr (Z = 40). Exploring the evolution of these properties as they move away from the subshell closure is of great interest.Purpose: The purpose of this study is to reproduce the spectroscopic properties of even-even 96–110Mo and 98–114 Ru isotopes and to determine the influence of shape coexistence. Method: We employed the interacting boson model with configuration mixing as the framework to calculate all the observables for Mo and Ru isotopes. We considered two types of configurations: 0-particle–0-hole and2-particle–2-hole excitations. The model parameters were determined using a least-squares fitting to match the excitation energies and the B(E 2) transition rates.Results: We obtained the excitation energies, B(E 2) values, two-neutron separation energies, nuclear radii, and isotope shifts for the entire chain of isotopes. Our theoretical results show good agreement with experimental data. Furthermore, we conducted a detailed analysis of the wave functions and obtained the mean-field energy surfaces and the nuclear deformation parameter, β, for all considered isotopes.Conclusions: Our findings reveal that shape coexistence plays a significant role in Mo isotopes, with the crossing of intruder and regular configurations occurring at neutron number 60 (A = 102), which induces a quantum phase transition. In contrast, in Ru isotopes, the intruder states have minimal influence, remaining at higher energies. However, at neutron number 60, also a quantum phase transition occurs in Ru isotopes. PB American Physical Society SN 2469-9985 SN 2469-9993 (electrónico) YR 2023 FD 2023-09 LK https://hdl.handle.net/10272/22832 UL https://hdl.handle.net/10272/22832 LA eng NO Maya-Barbecho, E., Baid, S., Arias, J. M., & García-Ramos, J. E. (2023). At the borderline of shape coexistence: Mo and Ru. In Physical Review C (Vol. 108, Issue 3). American Physical Society (APS). https://doi.org/10.1103/physrevc.108.034316 NO Oneof the authors (J.E.G.R.) thanksK.Heyde for his continuous advice and support. This workwas partially supportedby theConsejería deEconomía, Conocimiento, Empresas yUniversidadde la JuntadeAndalucía (Spain) underGroupsFQM-160andFQM-370, andunderProjects No.P20-00617,No.P20-01247, andNo.US-1380840, and also through Projects No. PID2019-104002GB-C21, No. PID2019-104002GB-C22,No.PID2020-114687GB-I00,No. PID2022-136228NB-C21,andNo.PID2022-136228NB-C22 fundedbyMCIN/AEI/10.13039/50110001103and“ERDF AwayofmakingEurope.”Resourcessupportingthiswork were provided by theCEAFMCand theUniversidad de HuelvaHighPerformanceComputer(HPC@UHU)fundedby ERDF/MINECOProjectNo.UNHU-15CE-2848. DS Repositorio Institucional de la Universidad de Huelva RD 30 may 2026