High-spin states inTe121,122: Identification of favored noncollective oblate states

Abstract

High-spin states up to Iϳ20ប have been studied in the 121,122 Te nuclei using the 116 Cd( 9 Be,xn͒ reaction at 37.8 MeV. In this spin regime, several favored noncollective oblate states (␥ϭϩ60°), where the singleparticle angular momenta generate the total nuclear spin, are predicted to coexist with weakly deformed collective structures. Theoretical expectations for such oblate states, based on TRS cranking calculations, are compared to the experimental results.

Effective field theory for nuclear vibrations with quantified uncertainties

“…122 Te exhibits a non-vibrational state already at the three-phonon level. The breakdown of the collective behavior is a consequence of competing single- particle motion, know to exist in tellurium isotopes [75][76][77][78][79][80], and signaled in 122 Te by the unusual energy ratios E(4 + 1 )/E(2 + 1 ) < 2 and E(6 + 1 )/E(4 + 1 ) < 1.5 [81]. The alignment of both valence nucleons and protons promoted across the Z = 50 shell gap breaks the spherical symmetry and give rise to non-collective deformed states.…”

Collective and noncollective excitations in122Te

“…1. The positiveparity ground band was established up to I π = 10 + and 12 + in investigations by Chowdhury et al [21] and Lee et al [22], respectively, and was later extended up to I π = 16 + by Paul et al [19]. Nag et al [20] reported positive-parity levels up to I = (25) and several side branches.…”

“…The level scheme of 122 Te, based on both present and previous results [19,20], is displayed in Fig. 1.…”

“…The structure of the low-spin levels in 122 Te was investigated in previous work [19][20][21][22]. Here, only the configuration assignments to the new high-spin states will be discussed.…”

“…In this paper, the results of a spectroscopic investigation of the high-spin structure of 122 Te are presented. The previously known level scheme [19][20][21][22] is extended to considerably higher spin. Maximally aligned states and high-energy transitions originating from core-breaking excitations have been observed.…”