Experimental investigation of shell-model excitation in Nb 90 up to high-spin states

Abstract

In-beam γ-ray spectroscopy study of odd-odd nucleus Nb90 is reported using the heavy-ion induced fusion evaporation reaction Cu65(Si30, 3n2p) at a beam energy of 120 MeV. The level scheme of Nb90 has been revised, with the addition of 13 new transitions and 13 new energy levels up to an excitation of 7.780 MeV and spin 19°. Shell-model calculations using the GWBXG interaction have been performed to understand the configuration and structure of the positive- and negative-parity states up to the highest observed spin. Calculations have identified multi-quasiparticle configurations with proton excitation from Z = 38 for generating high spin states. Moreover, no neutron excitation was found. © 2025 American Physical Society.