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The high-spin structures and isomers of the N = 81 isotones 135 Xe and 137 Ba are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in 136 Xe+ 238 U and (ii) 136 Xe+ 208 Pb MNT reactions employing the high-resolution Advanced Gamma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (iii), in the 136 Xe+ 198 Pt MNT reaction employing the γ-ray array GAMMASPHERE in combination with the gas-detector array CHICO, and (iv) via a 11 B+ 130 Te fusion-evaporation reaction with the HORUS γ-ray array at the University of Cologne. The high-spin level schemes of 135 Xe and 137 Ba are considerably extended to higher energies. The 2058-keV (19/2 − ) state in 135 Xe is identified as an isomer, closing a gap in the systematics along the N = 81 isotones. Its half-life is measured to be 9.0(9) ns, corresponding to a reduced transition probability of B(E2, 19/2 − → 15/2 − ) = 0.52(6) W.u. The experimentally-deduced reduced transition probabilities of the isomeric states are compared to shell-model predictions. Latest shell-model calculations reproduce the experimental findings generally well and provide guidance to the interpretation of the new levels.

The transitional nucleus 131 Xe is investigated after multinucleon transfer in the 136 Xe + 208 Pb and 136 Xe + 238 U reactions employing the high-resolution Advanced γ -Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and as an elusive reaction product in the fusion-evaporation reaction 124 Sn( 11 B,p3n) 131 Xe employing the High-efficiency Observatory for γ -Ray Unique Spectroscopy (HORUS) γ -ray array coupled to a double-sided silicon strip detector at the University of Cologne, Germany. The level scheme of 131 Xe is extended to 5 MeV. A pronounced backbending is observed at hω ≈ 0.4 MeV along the negative-parity one-quasiparticle νh 11/2 (α = −1/2) band. The results are compared to the high-spin systematics of the Z = 54 isotopes and the N = 77 isotones. Large-scale shell-model calculations employing the PQM130, SN100PN, GCN50:82, SN100-KTH, and a realistic effective interaction reproduce the experimental findings and provide guidance to elucidate the structure of the high-spin states. Further calculations in 129−132 Xe provide insight into the changing nuclear structure along the Xe chain towards the N = 82 shell

The transitional nuclei 132 Xe and 133 Xe are investigated after multinucleon-transfer (MNT) and fusionevaporation reactions. Both nuclei are populated (i) in 136 Xe + 208 Pb MNT reactions employing the highresolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (ii) in the 136 Xe + 198 Pt MNT reaction employing the GAMMASPHERE spectrometer in combination with the gas-detector array CHICO, and (iii) as an evaporation residue after a 130 Te(α,xn) 134−xn Xe fusion-evaporation reaction employing the HORUS γ -ray array at the University of Cologne. The high-spin level schemes are considerably extended above the J π = (7 − ) and (10 + ) isomers in 132 Xe and above the 11/2 − isomer in PHYSICAL REVIEW C 96, 024321 (2017) isotones. Shell-model calculations employing the SN100PN and PQM130 effective interactions reproduce the experimental findings and provide guidance to the interpretation of the observed high-spin features.