Shape coexistence and octupole vibrations inSe74

Abstract

The results of a study of high spin states of ' Se using two reactions, "Ni(' F,3p) and 'Ti("S, a2p), are presented. The ground-state band is extended up to J" =(24+), and three other bands are also extended to higher spins than those known previously. Lifetimes of states in the ground-state band (J =6-16) and an odd-spin negative-parity band (J =9-13) measured by the Doppler-shift attenuation method are reported. A rotational band built on the 854-keV 0 state is proposed, allowing the study of two coexisting K"=0+ bands to high spin. It is also concluded that energy and lifetime information support an octupole-band interpretation for the odd-spin negativeparity band.

Transition strengths and shapes of 2-qp bands in 74Se and 76Kr

“…Most of the transitions in Kr reported in refs [2] and [4] and in Se reported in refs [1] and [3] have been observed in our experiment. The sum gated spectra were used for line shape analysis.…”

“…However, in the present study it is argued that later bands are quasi neutron in character. The lifetimes of the levels of band 5 of Se were previously measured by Cottle et al [1] and are not shown in table 1. The measured lifetimes for few levels match quite well with the previous measurements except for the 9 state of Kr.…”

“…The even-even AE ¼ nuclei Se and Kr show interesting structure properties including shape coexistence in the yrast bands [1,2]. In addition to the +ve parity yrast bands, other ve parity bands with strong E2 transitions have recently been observed in both the nuclei [2][3][4].…”

Shape coexistence and high-Kstates in74Se populated following theβdecay ofMcCutchan1, Lister2, Ahn3 et al. 2013Phys. Rev. C10071View full textAdd to dashboardCite

“…Similarly, 74 Se and its neighbors have been successfully described by the supersymmetry scheme in the vibrational limit [14]. A more recent high-spin study proposed [15] new spin assignments in 74 Se which changed the prior interpretation of the so-called γ band into a deformed coexisting band built upon the first excited 0 + state. This assignment was later refuted [16], and the postulated γ band re-established as being built upon the 2 + 2 level.…”

High spin and shape coexistence inSe73

“…Until recently it was thought that the coexistence occurred between a vibrational band built on a nearly spherical oblate state and a we11-deformed prolate rotational band. A recent study by Cottle et al [23] suggests that, in Se, the coexisting bands are both built on well-deformed states. The efFect of an odd nucleon added to a shape-coexistent even-even core is not well understood.…”