Rotational bands on 9/2⁺ proton- hole states in ¹¹²Sb

Abstract

High-spin states of the doubly-odd ¹¹²Sb were studied by in-beam spectroscopy using the ⁸⁸Sr (²⁸Si, p3n) and ⁸⁹Y (²⁹Si, α2n) fusion-evaporation reactions at beam energies of 120 and 108 MeV, respectively. γ−γ, charged particle-γ−γ coincidences, and γ−γ angular correlation analyses were employed for determining the level scheme of ¹¹²Sb. In the present work, all the levels except for low-lying states in ¹¹²Sb were newly established. Two ΔI = 1 strongly coupled bands were observed; one is a negative-parity band that is similar to those observed in the neighboring doubly-odd Sb isotopes and the other is a positive-parity band that has a new type structure not observed in the other isotopes. From the similarity of the properties of these ΔI = 1 bands to the bands built on 9/2⁺ 2p−1h states in the odd-A Sb isotopes, we suggest that these two ΔI = 1 bands should be associated with the [π(g_9/2)⁻¹ ⊗ νh_11/2] and [π(g_9/2)⁻¹νg_7/2] configurations, respectively.