High-spin Structures of the Near-spherical Nuclei $^{91,92}$Zr

Abstract

In the present work, we have interpreted recently available experimental data for high-spin states of the near-spherical nuclei 91,92 Zr, using the shell-model calculations within the full f 5/2 , p 3/2 , p 1/2 , g 9/2 model space for protons and valence neutrons in g 9/2 , g 7/2 , d 5/2 orbits. We have employed a truncation for the neutrons due to huge matrix dimensions, by allowing one neutron excitation from g 9/2 orbital to d 5/2 and g 7/2 orbitals. Results are in good agreement with the available experimental data. Thus, theoretically, we have identified the structure of many high-spin states, which were tentatively assigned in the recent experimental work. The 91 Zr 21/2 + isomer lies at low-energy region due to fully aligned spins of two g 9/2 protons and one d 5/2 neutron.