Revisiting band structures in ¹¹⁸Xe nucleus via in-beam γ-ray spectroscopy*

Abstract

The neutron deficient Xe nuclei with A ≈ 120 are predicted to have strong octupole correlation at low spins. In
the present work, an attempt was made to improve upon the level scheme and also to look into the signatures of
octupole correlation in 118Xe via high spin γ-ray spectroscopy. High spin states in 118Xe have been populated via
93Nb(28Si,p2n)118Xe fusion-evaporation reaction at a beam energy of 115 MeV provided by the 15 UD pelletron
accelerator facility at IUAC, New Delhi. In the experiment, seven new γ-transitions have been found and are placed
appropriately in the level scheme. Theoretical study using the triaxial projected shell model (TPSM) approach
suggests that the first bandcrossing is due to the alignment of two neutrons, and a parallel band tracking the yrast
configuration is the γ-band built on the two-quasiparticle state. Enhanced E1 transition rates measured between
opposite parity bands, involving νh11/2 and νd5/2 orbitals having ∆j = ∆l = 3, indicates the presence of octupole
correlation in this nucleus