The transitional nucleus Xe-131 is investigated after multinucleon transfer in the Xe-136 + Pb-208 and Xe-136 +U-238 reactions employing the high-resolution Advanced gamma-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 Sn-124(B-11) ,p3n)Xe-131 employing the High-efficiency Observatory for gamma-Ray Unique Spectroscopy (HORUS) gamma-ray array coupled to a double-sided silicon strip detector at the University of Cologne, Germany. The level scheme of Xe-131 is extended to 5 MeV. A pronounced backbending is observed at (h) over bar omega approximate to 0.4 MeV along the negative-parity one-quasiparticle vh(11/12)(alpha = -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 Xe129-132 provide insight into the changing nuclear structure along the Xe chain towards the N = 82 shell closure. Proton occupancy in the pi 0h(11/2) orbital is found to be decisive for the description of the observed backbending phenomenon.

L. Kaya,1, a A. Vogt,1 P. Reiter,1 M. Siciliano,2, 3 B. Birkenbach,1 A. Blazhev,1 L. Coraggio,4 E. Teruya,5 N. 3 Yoshinaga,5 K. Higashiyama,6 K. Arnswald,1 D. Bazzacco,7 A. Bracco,8 B. Bruyneel,9 L. Corradi,3 F. C. L. Crespi,8 4 G. de Angelis,3 J. Eberth,1 E. Farnea,7, b E. Fioretto,3 C. Fransen,1 B. Fu,1 A. Gadea,10 A. Gargano,4 A. Giaz,8 A. 5 Görgen,11, 12, 13 A. Gottardo,3 K. Hadyńska-Klęk,3 H. Hess,1 R. Hetzenegger,1 R. Hirsch,1 N. Itaco,4, 14 P. R. John,15 6 J. Jolie,1 A. Jungclaus,16 W. Korten,17 S. Leoni,8 L. Lewandowski,1 S. Lunardi,2, 7 R. Menegazzo,7 D. Mengoni,18, 2, 7 7 C. Michelagnoli,19 T. Mijatović,20 G. Montagnoli,2, 7 D. Montanari,2, 7 C. Müller-Gatermann,1 D. Napoli,3 Zs. 8 Podolyák,21 G. Pollarolo,22 A. Pullia,8 M. Queiser,1 F. Recchia,2, 7 D. Rosiak,1 N. Saed-Samii,1 E. Şahin,23 F. 9 Scarlassara,2, 7 D. Schneiders,1 M. Seidlitz,1 B. Siebeck,1 J. F. Smith,24 P.-A. Söderström,25 A. M. Stefanini,3 T. 10 Steinbach,1 O. Stezowski,26 S. Szilner,20 B. Szpak,27 C. Ur,7 J. J. Valiente-Dobón,3 K. Wolf,1 and K. O. Zell1 11

Kaya, L.; Vogt, A.; Reiter, P.; Siciliano, M.; Birkenbach, B.; Blazhev, A.; Coraggio, L.; Teruya, E.; Yoshinaga, N.; Higashiyama, K.; Arnswald, K.; Bazzacco, D.; Bracco, A.; Bruyneel, B.; Corradi, L.; Crespi, F.C.L.; de Angelis, G.; Eberth, J.; Farnea, E.; Fioretto, E.; Fransen, C.; Fu, B.; Gadea, A.; Gargano, A.; Giaz, A.; Görgen, A.; Gottardo, A.; Hadyska-Klk, K.; Hess, H.; Hetzenegger, R.; Hirsch, R.; Itaco, N.; John, P.R.; Jolie, J.; Jungclaus, A.; Korten, W.; Leoni, S.; Lewandowski, L.; Lunardi, S.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Mijatovi, T. ; Montagnoli, G.; Montanari, D.; Müller-Gatermann, C.; Napoli, D.; Podolyák, Zs.; Pollarolo, G.; Pullia, A.; Queiser, M.; Recchia, F.; Rosiak, D.; Saed-Samii, N.; ahin, E.; Scarlassara, F.; Schneiders, D.; Seidlitz, M.; Siebeck, B.; Smith, J.F. ; Söderström, P.-A.; Stefanini, A.M.; Steinbach, T.; Stezowski, O.; Szilner, S.; Szpak, B.; Ur, C.; Valiente-Dobón, J.J.; Wolf, K.; Zell, K.O.

The transitional nuclei Xe-132 and Xe-133 are investigated after multinucleon-transfer (MNT) and fusionevaporation reactions. Both nuclei are populated (i) in Xe-136 + 2(08P)b MNT reactions employing the highresolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (ii) in the Xe-136 + Pt-198 MNT reaction employing the GAMMASPHERE spectrometer in combination with the gas-detector array CHICO, and (iii) as an evaporation residue after a Te-130(alpha, xn) Xe134-xn fusion-evaporation reaction employing the HORUS gamma-ray array at the University of Cologne. The high-spin level schemes are considerably extended above the J(pi) = (7(-)) and (10+) isomers in Xe-132 and above the 11/2(-) isomer in Xe-133. The results are compared to the high-spin systematics of the Z = 54 as well as the N = 78 and N = 79 chains. Furthermore, evidence is found for a long-lived (T-1/2 >> mu s) isomer in Xe-133 which closes a gap along the N = 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.

Lifetimes of the 2(1)(+) states in Ti-44, Cr-48,Cr-50, and Fe-52 were determined with high accuracy exploiting the recoil distance Doppler-shift method. The reduced E2 transition strengths of Ti-44 and Fe-52 differ considerably from previously known values. A systematic increase in collectivity is found for the N = Z nuclei compared to neighboring isotopes. The B(E2) values along the Ti, Cr, and Fe isotopic chains are compared to shell-model calculations employing established interactions for the 0 f 1p shell, as well as a novel effective shell-model Hamiltonian starting from a realistic nucleon-nucleon potential. The theoretical approaches underestimate the B(E2) values for the lower-mass Ti isotopes. Strong indication is found for particle-hole cross-shell configurations, recently corroborated by similar results for the neighboring isotone Ca-42. (C) 2017 The Author(s). Published by Elsevier B.V.

© 2017 American Physical Society. The high-spin structures and isomers of the N=81 isotones Xe135 and Ba137 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in Xe136+U238 and (ii) Xe136+Pb208 MNT reactions employing the high-resolution Advanced Gamma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (iii) in the Xe136+Pt198 MNT reaction employing the γ-ray array GAMMASPHERE in combination with the gas-detector array CHICO, and (iv) via a B11+Te130 fusion-evaporation reaction with the HORUS γ-ray array at the University of Cologne. The high-spin level schemesof Xe135 and Ba137 are considerably extended to higher energies. The 2058-keV (19/2-) state in Xe135 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.

Lifetimes of excited states in the neutron-deficient nucleus Zn-61 were measured employing the recoil-distance Doppler-shift (RDDS) and the electronic fast-timing methods at the University of Cologne. The nucleus of interest was populated as an evaporation residue in Ca-40(Mg-24, n2p)Zn-61 and Ni-58(alpha,n)Zn-61 reactions at 67 and 19 MeV, respectively. Five lifetimes were measured for the first time, including the lifetime of the 5/2(1)(-) isomer at 124 keV. Short lifetimes from the RDDS analysis are corrected for Doppler-shift attenuation (DSA) in the target and stopper foils. Ambiguous observations in previous measurements were resolved. The obtained lifetimes are compared to predictions from different sets of shell-model calculations in the fp, f(5/2)pg(9/2), and multishell fp-g(9/2)d(5/2) model spaces. The band built on the 9/2(1)(+) state exhibits a prolate deformation with beta approximate to 0.24. Especially, the inclusion of cross-shell excitation into the 1d(5/2) orbital is found to be decisive for the description of collectivity in the first excited positive-parity band.

The transitional nuclei $^{132}\mathrm{Xe}$ and $^{133}\mathrm{Xe}$ are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in $^{136}\mathrm{Xe}+^{208}\mathrm{Pb}$ MNT reactions employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (ii) in the $^{136}\mathrm{Xe}+^{198}\mathrm{Pt}$ MNT reaction employing the GAMMASPHERE spectrometer in combination with the gas-detector array CHICO, and (iii) as an evaporation residue after a $^{130}\mathrm{Te}(\ensuremath{\alpha},xn)^{134\ensuremath{-}xn}\mathrm{Xe}$ fusion-evaporation reaction employing the HORUS $\ensuremath{\gamma}$-ray array at the University of Cologne. The high-spin level schemes are considerably extended above the ${J}^{\ensuremath{\pi}}=({7}^{\ensuremath{-}})$ and $({10}^{+})$ isomers in $^{132}\mathrm{Xe}$ and above the $11/{2}^{\ensuremath{-}}$ isomer in $^{133}\mathrm{Xe}$. The results are compared to the high-spin systematics of the $Z=54$ as well as the $N=78$ and $N=79$ chains. Furthermore, evidence is found for a long-lived (${T}_{1/2}\ensuremath{\gg}1\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{s}$) isomer in $^{133}\mathrm{Xe}$ which closes a gap along the $N=79$ 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.

Citation for published version (APA): Vogt, A., Siciliano, M., Birkenbach, B., Reiter, P., Hadynska-Klek, K., Wheldon, C., Valiente Dobon, JJ., Teruya, E., Yoshinaga, N., Arnswald, K., Bazzacco, D., Blazhev, A., Bracco, A., Bruyneel, B., Chakrawarthy, R. S., Chapman, R., Cline, D., Corradi, L., Crespi, F. C. L., ... Zell, K. O. (2017). High-spin structures in 132 Xe and 133 Xe and evidence for isomers along the N = 79 isotones. Physical Review C (Nuclear Physics), 96, [024321]. https://doi.org/10.1103/PhysRevC.96.024321

Excited states with intermediate and high spins in $^{33}\mathrm{P}$ and $^{33}\mathrm{S}$ have been populated using the $^{26}\mathrm{Mg}(^{13}\mathrm{C},np\ensuremath{\alpha})$ and $^{26}\mathrm{Mg}(^{13}\mathrm{C},2n\ensuremath{\alpha})$ fusion-evaporation reactions. The level schemes of both nuclei have been considerably extended. Utilizing $\ensuremath{\gamma}\ensuremath{\gamma}$ angular correlations the spin-parity assignment of the new excited states in $^{33}\mathrm{P}$ has been investigated. The experimentally determined results from both nuclei were compared to $0\ensuremath{\hbar}\ensuremath{\omega}$ and $1\ensuremath{\hbar}\ensuremath{\omega}$ truncated p-sd-pf shell-model calculations utilizing the PSDPF interaction, showing a very good agreement between experiment and theory.

Excited states with intermediate and high spins in P-33 and S-33 have been populated using the Mg-26(C-13, np alpha) and Mg-26(C-13,2n alpha) fusion-evaporation reactions. The level schemes of both nuclei have been considerably extended. Utilizing gamma gamma angular correlations the spin-parity assignment of the new excited states in P-33 has been investigated. The experimentally determined results from both nuclei were compared to 0 (h) over bar omega and 1 (h) over bar omega truncated p-sd-pf shell-model calculations utilizing the PSDPF interaction, showing a very good agreement between experiment and theory.