High-spin states in odd-massSb113−119:

Abstract

Properties of high-spin states in """"""Sb have been studied via the "Cd( Li,3n)" +'Sb reactions. Using Ge(Li) and Si(Li) detectors, in-beam measurements of y-ray excitation functions, y-y coincidences, y-ray angular distributions, and pulsed beam-y timing spectra weie made to determine level energies, decay schemes, y-ray multipolarities, J assignments, isomeric lifetimes, and a g factor. Systematic hJ = 1 bands built on low-lying 9/2+ proton-hole (2p-1h) states were observed in these nuclei. The bandheads that involve the excitation of a 1g9/2 proton across the Z = 50 shell achieve an energy minimum near the middle of the neutron shell. The observed properties of these bands are consistent with significant prolate deformations; the band spacings imply a deformation asymmetry of y = 20 in a triaxial rotor model. In addition, single-particle and single-particle plus core-excitation states were observed in these Sb nuclei. Two isomers were identified, a 19/2 state at 2796 keV in '"Sb (7 = 230+4 ns and g. = + 0.290+0,005) and a (27/2+) state in " Sb (7' = 1.23+ 0.13 s). NUCLEAR REACTIONSCd(6Li, 3n) " '~Sb measured y-y coincidences, y(E, O, t), spin rotation in B= 10.3 ko; deduced level schemes in odd-mass Sb, y multipolarities, J', T&&2, g-factor. Enriched targets, Ge(Li) detectors.

Core-coupled protons,f7/2intruder states, and competingg9/2proton and neutron structures inChiara1, Stefanescu2, Walters3 et al. 2012Phys. Rev. C

“…In odd-A 113−123 Sb, strongly coupled band structures with 9/2 + bandheads were observed and attributed to an analogous excitation of g 9/2 protons across the Z = 50 shell gap [66].…”

“…Summary of the shell-model calculations Overall, the observed positive-parity levels for 65,67 Cu can be described better in terms of the weak coupling of a p 3/2 proton to the negative-parity states of the 64,66 Ni cores than with shell-model calculations using the currently available JUN45 and jj44b effective interactions. The summary of Sec.…”

“…The evolution of codes designed to take advantage of advances in computing speed and power will ultimately allow consideration of these large dimensions. To this end, detailed level structures of 65,67 Cu, especially in comparison with the reasonably well established decay schemes of their corresponding cores, 64,66 Ni, represent a valuable addition to the available data for testing new effective interactions.…”

Collective and noncollective states in120Te

“…Nuclei near the Z = 50 proton shell closure are known to exhibit shape coexistence [1], which has been investigated in detail in many neutron deficient isotopes of Sn [2], Sb [3][4][5], and Te [6,7]. The available small number of valence particles or holes can break the spherical symmetry and, thus, drive the nucleus towards (small) deformation.…”

Electromagnetic moments of the 7+ rotational bandhead in116Sb

“…This state has also been observed in [ 1] where its half-life was measured as 10.3 ns, and in a very recent l t3In(~, n) study [7]. The occurrence of the positive parity rotational-like band suggests the presence of a deformation which could be also associated to the g9/2 proton-hole excitation known to be responsible for shape coexistence in Sb nuclei [4,5,[8][9][10]. To check this assumption we have performed measurements to determine the static electromagnetic moments of the 7 § isomeric bandhead in ~6Sb and the obtained results are reported in the present paper.…”