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13 pags., 9 figs., 2 tabs., Excited states of In129 populated following the β decay of Cd129 were experimentally studied with the GRIFFIN spectrometer at the ISAC facility of TRIUMF, Canada. A 480-MeV proton beam was impinged on a uranium carbide target and Cd129 was extracted using the Ion Guide Laser Ion Source (IG-LIS). β and γ rays following the decay of Cd129 were detected with the GRIFFIN spectrometer comprising the plastic scintillator SCEPTAR and 16 high-purity germanium (HPGe) clover-type detectors. From the β-γ-γ coincidence analysis, 32 new transitions and seven new excited states were established, expanding the previously known level scheme of In129. The logft values deduced from the β-feeding intensities suggest that some of the high-lying states were populated by the ν0g7/2→π0g9/2 allowed Gamow-Teller (GT) transition, which indicates that the allowed GT transition is more dominant in the Cd129 decay than previously reported. Observation of fragmented Gamow-Teller strengths is consistent with theoretical calculations., The authors would like to thank the operators at the TRIUMF-ISAC facility for providing the radioactive beam. This work was partially supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canada Research Chairs Program, NSERC Discovery Grants No. SAPIN-2014-00028 and No. RGPAS 462257-2014, the NSERC CREATE Program IsoSiM (Isotopes for Science and Medicine), the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P, the US National Science Foundation (NSF) under Contract No. NSF14-01574, and the Mexican DGAPA-UNAM program under Contract No. PAPIIT-IN110418. The GRIFFIN spectrometer was funded by the Canada Foundation for Innovation (CFI), TRIUMF, and the University of Guelph. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada (NRC). Y.S. would like to thank Jorge Agramunt (IFIC Valencia, Spain) for providing a program for fitting the time distribution of β particles.The authors would like to thank the operators at the TRIUMF-ISAC facility for providing the radioactive beam. This work was partially supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canada Research Chairs Program, NSERC Discovery Grants No. SAPIN-2014-00028 and No. RGPAS 462257-2014, the NSERC CREATE Program IsoSiM (Isotopes for Science and Medicine), the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P, the US National Science Foundation (NSF) under Contract No. NSF14-01574, and the Mexican DGAPA-UNAM program under Contract No. PAPIIT-IN110418. The GRIFFIN spectrometer was funded by the Canada Foundation for Innovation (CFI), TRIUMF, and the University of Guelph. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada (NRC). Y.S. would like to thank Jorge Agramunt (IFIC Valencia, Spain) for providing a program for fitting the time distribution of β particles.

12 pags., 5 figs., 3 tabs., The β decay of Hg207 into the single-proton-hole nucleus Tl207 has been studied through γ-ray spectroscopy at the ISOLDE Decay Station (IDS) with the aim of identifying states resulting from coupling of the πs1/2-1, πd3/2-1, and πh11/2-1 shell model orbitals to the collective octupole vibration. Twenty-two states were observed lying between 2.6 and 4.0 MeV, eleven of which were observed for the first time, and 78 new transitions were placed. Two octupole states (s1/2-coupled) are identified and three more states (d3/2-coupled) are tentatively assigned using spin-parity inferences, while further h11/2-coupled states may also have been observed for the first time. Comparisons are made with state-of-the-art large-scale shell model calculations and previous observations made in this region, and systematic underestimation of the energy of the octupole vibrational states is noted. We suggest that in order to resolve the difference in predicted energies for collective and noncollective t=1 states (t is the number of nucleons breaking the Pb208 core), the effect of t=2 mixing may be reduced for octupole-coupled states. The inclusion of mixing with t=0,2,3 excitations is necessary to replicate all t=1 state energies accurately., The research leading to these results has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No. 654002. Support from the European Union Seventh Framework through ENSAR Contract No. 262010, the Science and Technology Facilities Council (UK), the MINECO Projects No. FPA2015-64969-P and No. FPA2017-87568-P (Spain), FWOVlaanderen (Belgium), GOA/2015/010 (BOF KU Leuven), the Excellence of Science Programme (EOS-FWO), the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), the German BMBF under Contract No. 05P18PKCIA + “Verbundprojekt 05P2018,” the Polish National Science Centre under Contracts No. UMO-2015/18/M/ST2/00523 and No. UMO-2019/33/N/ST2/03023, the National Science Foundation (US) Grant No. PHY-1811855 and the Romanian IFA project CERN-RO/ISOLDE is acknowledged. P.H.R. and S.M.J. acknowledge support from the UK Department for Business, Energy and Industrial Strategy via the National Measurement Office.

The β decay of 207Hg into the single-proton-hole nucleus 207Tl has been studied through γ-ray spectroscopy at the ISOLDE Decay Station (IDS) with the aim of identifying states resulting from coupling of the πs−11/2, πd−13/2, and πh−111/2 shell model orbitals to the collective octupole vibration. Twenty-two states were observed lying between 2.6 and 4.0 MeV, eleven of which were observed for the first time, and 78 new transitions were placed. Two octupole states (s1/2-coupled) are identified and three more states (d3/2-coupled) are tentatively assigned using spin-parity inferences, while further h11/2-coupled states may also have been observed for the first time. Comparisons are made with state-of-the-art large-scale shell model calculations and previous observations made in this region, and systematic underestimation of the energy of the octupole vibrational states is noted. We suggest that in order to resolve the difference in predicted energies for collective and noncollective t=1 states (t is the number of nucleons breaking the 208Pb core), the effect of t=2 mixing may be reduced for octupole-coupled states. The inclusion of mixing with t=0,2,3 excitations is necessary to replicate all t=1 state energies accurately.

6 pags., 4 figs., 1 tab., The β decay of Hg208 into the one-proton hole, one neutron-particle Tl81208127 nucleus was investigated at CERN-ISOLDE. Shell-model calculations describe well the level scheme deduced, validating the proton-neutron interactions used, with implications for the whole of the N>126, Z, This work was supported by the European Union under Contracts No. 262010 (ENSAR) and No. 654002 (ENSAR2), the Science and Technology Facilities Council (UK), the German BMBF under Contract No. 05P18PKCIA and “Verbundprojekt 05P2018,” the MINECO Projects No. FPA2015-65035-P, No. RTI2018- 098868-B-I00, No. FPA2015-64969-P, and No. FPA2017- 87568-P (Spain), FWO-Vlaanderen (Belgium), GOA/ 2015/010 (BOF KU Leuven), the Excellence of Science programme (EOS-FWO), the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), the Romanian IFA project CERN-RO/ISOLDE and the Polish National Science Centre under Contracts No. UMO-2015/18/M/ST2/00523 and No. UMO-2019/33/N/ST2/03023. P. H. R. and S. M. J. acknowledge support from the UK Department for Business, Energy and Industrial Strategy via the National Measurement Office. Zs. P. acknowledges support from the ExtreMe Matter Institute EMMI at the GSI Helmholtzzentrum fr Schwerionenforschung, Darmstadt, German

11 pags., 10 figs., 3 tabs., We report on new γ-ray spectroscopy results from β decays of In99 and Sn101. 30 new γ rays were observed following the β decay of In99, and inconsistencies in the literature with respect to the γ rays following the β decay of Sn101 were addressed with two confirmed cases and two new transitions. The experimental γ-ray energies, intensities, and coincidence relationships are discussed with shell model calculations, where theoretical β-decay branching ratios from the parent nuclei and γ-ray cascades of excited states from the daughter nuclei were combined to generate hypothetical βγ spectra and βγγ coincidence matrices. The most intense β-delayed γ-ray branches in both Cd99 and In101 were well reproduced with this approach, and several γ rays were assigned to new excited states based on their good agreement with shell model predictions., The authors would like to thank the personnel at the RIKEN Nishina Center for providing the exotic radioactive isotope beam with record intensities. This experiment was performed at RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo. We acknowledge the EUROBALL Owners Committee for loaning the germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors of EURICA. Support for the WAS3ABi setup was provided by the Rare Isotope Science Project, funded by the Ministry of Education, Science and Technology (MEST) and National Research Foundation (NRF) of Korea, as well as KAKENHI (Grant No. 25247045) of Japan Society for the Promotion of Science (JSPS). This work was supported by the Institute for Basic Science (IBS-R031-D1). The authors acknowledge also the support of the DFG cluster of excellence “Origin and Structure of the Universe,” German BMBF under Contracts No. 05P15PKFNA and No. 05P19PKFNA, and the Spanish Ministerio de Economía y Competitividad via Project No. FPA2017-84756-C4-2-P. Part of the research was funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada and also supported by FJNSP LIA (French-Japanese International Associated Laboratory for Nuclear Structure Problems)

6 pags., 5 figs., A γ-decaying isomeric state (τ1/2=197-17+19 ns) has been identified in Cd96, which is one α particle away from the last known bound N=Z nucleus, Sn100. Comparison of the results with shell-model calculations has allowed a tentative experimental level scheme to be deduced and the isomer to be interpreted as a medium-spin negative-parity spin trap based on the coupling of isoscalar (T=0) and isovector (T=1) neutron-proton pairs. The data also suggest evidence for the population of a 9+ T=1 state, which is predicted by shell-model calculations to be yrast. Such a low-lying T=1 state, which is unknown in lighter mass even-even self-conjugate nuclei, can also be interpreted in terms of the coupling of T=0 and T=1 neutron-proton pairs., This work was partially supported by the German BMBF Grants No. 05P12PKFNE and No. 05P15RDFN1, the UK STFC under Grants No. ST/J000124/1 and No. ST/L005727/1, the Natural Sciences and Engineering Research Council (NSERC) of Canada, the U.S. DOE Grant No. DE-FG02-91ER40609, KAKENHI under Grant No. 25247045, and the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2014-57196-C5-4-P.

9 pags., 6 figs., 2 tabs., A systematic study was performed of microsecond γ-decaying isomers around Sn100 produced in a fragmentation reaction of a Xe124 beam at 345 MeV/u at the Radioactive Ion Beam Factory of the RIKEN Nishina Center in Saitama, Japan. Half-lives of isomeric states in that region were remeasured allowing us to improve the currently available experimental information. Reduced transition probabilities were deduced and compared to shell-model calculations in various model spaces. The recently reported low-energy transitions in Rh92 and Ag96 were remeasured with improved precision. Additionally, experimental information on isomeric ratios, including five new ones, were extracted and compared to a previous experimental study and the sharp cutoff model of fragmentation reaction., This work was carried out at the RIBF operated by the RIKEN Nishina Center, RIKEN and CNS, University of Tokyo. We acknowledge the EUROBALL Owners Committee for the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of cluster detectors. This work was partly supported by the German BMBF under Contracts No. 05P12PKFNE and No. 05P15PKFNA, the U.S. Department of Energy under Grant No. DE-FG02-91ER40609, JSPS KAKENHI Grant No. KAKENHI 25247045, and the UK STFC under Grants No. ST/J000124/1, No. ST/L005727/1, and No. ST/P003885/1. G.H. was supported by the Bonn-Cologne Graduate School of Physics and Astronomy.

6 pags., 4 figs., tab. -- Rapid Communications, We report on new or more precise half-lives, beta-decay endpoint energies, and beta-delayed proton emission branching ratios of(91) Pd, Cd-95,In-97, and Sn-99. The measured values are consistent with known mirror transitions in lighter T-z = -1/2 nuclei, shell-model calculations, and various mass models. In addition to the beta -decaying (9/2(+)) ground state, circumstantial evidence for a short-lived, proton-emitting isomer with spin (1 /2(-)) was found in(97)In. Based on the experimental data, a semiempirical theory on proton emission, and shell-model calculations, the proton separation energy of the In-97 ground state was determined to be -0.10 +/- 0.19 MeV. The existence of the short-lived, proton-unstable (1 /2(-)) isomer in In-97 establishes Cd-9S as an rp-process waiting point., This experiment was performed at RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo.We acknowledge the EUROBALL Owners Committee for loaning the germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors of EURICA. Support for theWAS3ABi setup was provided by the Rare Isotope Science Project, funded by the Ministry of Education, Science and Technology (MEST) and National Research Foundation (NRF) of Korea, as well as KAKENHI (Grant No. 25247045) of the Japan Society for the Promotion of Science (JSPS). The authors acknowledge the support of the DFG cluster of excellence “Origin and Structure of the Universe,” German BMBF under Contract No. 05P15PKFNA and the Spanish Ministerio de Economa y Competitividad via Project No. FPA2014-57196-C5-4-P. Part of the research was funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada and also supported by FJ-NSP (French-Japanese International Associated Laboratory for Nuclear Structure Problems).

A. Jungclaus et al. ; 6 págs.; 4 figs. ; Rapid Communications, For the first time, the γ decay of excited states has been observed in a nucleus situated in the quadrant south-east of doubly magic Sn132, a region in which experimental information so far is limited to ground-state properties. Six γ rays with energies of 50, 86, 103, 227, 357, and 602 keV were observed following the β-delayed neutron emission from Cd85133, populated in the projectile fission of a U238 beam at the Radioactive Isotope Beam Factory at RIKEN within the EURICA project. The new experimental information is compared to the results of a modern realistic shell-model calculation, the first one in this region very far from stability, focusing in particular on the π0g9/2-1 - ν1f7/2 particle-hole multiplet in In83132. In addition, theoretical estimates based on a scaling of the two-body matrix elements for the πh11/2-1 - νg9/2 analog multiplet in Tl127208, one major proton and one major neutron shell above, are presented. ©2016 American Physical Society, We thank the staff of the RIKEN Nishina Center accelerator complex for providing stable beams with high intensities to the experiment. We acknowledge the EUROBALL Owners Committee for the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors. This work was supported by the Spanish Ministerio de Ciencia e Innovación under Contract No. FPA2011-29854-C04 and the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2014-57196-C5- 4-P, the Generalitat Valenciana (Spain) under Grant No. PROMETEO/2010/101, the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. NRF-2012R1A1A1041763), the Priority Centers Research Program in Korea (2009-0093817), OTKA Contract No. K-100835, JSPS KAKENHI (Grant No. 25247045), the European Commission through the Marie Curie Actions call PEOPLE-2011FP7-IEF under Contract No. 300096 and the German BMBF (No. 05P12RDCIA and No. 05P12RDNUP), and Helmholtz International Center for FAIR.

A. Jungclaus et al.; 8 págs.; 5 figs.; 3 tabs., The β decay of the semi-magic nucleus Cd130 has been studied at the RIBF facility at the RIKEN Nishina Center. The high statistics of the present experiment allowed for a revision of the established level scheme of In130 and the observation of additional β feeding to high-lying core-excited states in In130. The experimental results are compared to shell-model calculations employing a model space consisting of the full major N=50-82 neutron and Z=28-50 proton shells and the NA-14 interaction, and good agreement is found. ©2016 American Physical Society, We thank the staff of the RIKEN Nishina Center accelerator complex for providing stable beams with high intensities to the experiment. We acknowledge the EUROBALL Owners Committee for the loan of germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors. This work was supported by the Spanish Ministerio de Ciencia e Innovación under contract FPA2011-29854-C04 and the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2014-57196-C5- 4-P, the Generalitat Valenciana (Spain) under Grant No. PROMETEO/2010/101, the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (NRF-2014S1A2A2028636, 2016K1A3A7A09005579), the Priority Centers Research Program in Korea (2009-0093817), OTKA Contract No. K-100835, JSPS KAKENHI (Grant No. 25247045), the European Commission through the Marie Curie Actions call FP7-PEOPLE-2011-IEF under Contract No. 300096, the US Department of Energy, Office of Nuclear Physics, under Contract No.DE-AC02-06CH11357, the STFC (UK), the “RIKEN foreign research program,” the German BMBF (No. 05P12RDCIA, No. 05P12RDNUP, and No. 05P12PKFNE), HIC for FAIR, the DFG cluster of excellence “Origin and Structure of the Universe,” and DFG (Contract No. KR2326/2-1).

J. Taprogge et al.; 11 pags.; 8 figs.; 2 tabs.; PACS number(s): 23.20.Lv, 23.40.−s, 21.60.Cs, 27.60.+j, ©2015 American Physical Society. The β decay of 129Cd, produced in the relativistic fission of a 238U beam, was experimentally studied at the RIBF facility at the RIKEN Nishina Center. From the γ radiation emitted after the β decays, a level scheme of 129In was established comprising 31 excited states and 69 γ -ray transitions. The experimentally determined level energies are compared to state-of-the-art shell-model calculations. The half-lives of the two β-decaying states in 129Cd were deduced and the β feeding to excited states in 129In were analyzed. It is found that, as in most cases in the Z < 50, N 82 region, both decays are dominated by the ν0g7/2 → π0g9/2 Gamow–Teller transition, although the contribution of first-forbidden transitions cannot be neglected., This work was supported by the Spanish Ministerio de Ciencia e Innovacion under contracts FPA2009-13377-C02 and FPA2011-29854- C04, the Generalitat Valenciana (Spain) under grant PROMETEO/2010/101, the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. NRF-2012R1A1A1041763), the Priority Centers Research Program in Korea (2009-0093817), OTKA contract number K-100835, JSPS KAKENHI (Grant No. 25247045), the European Commission through the Marie Curie Actions call FP7-PEOPLE-2011-IEF under Contract No. 300096, the US Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357, the “RIKEN foreign research program,” and the German BMBF (No. 05P12RDCIA and 05P12RDNUP) and HIC for FAIR.

Reduced transition strengths of the deexciting transitions from the first two excited states in 33Ar were measured in a relativistic Coulomb excitation experiment at the GSI Helmholtz center. The radioactive ion beam was produced by fragmentation of a primary 36Ar beam on a 9Be target followed by the selection of the reaction product of interest via the GSI Fragment Separator. The 33Ar beam hit a secondary 197Au target with an energy of approximately 145 MeV/nucleon. An array of high-purity germanium cluster detectors and large-volume BaF2 scintillator detectors were employed for γ -ray spectroscopy at the secondary target position. The Lund-York-Cologne Calorimeter was used to track the outgoing ions and to identify the nuclear reaction channels. For the two lowest energy excited states of 33Ar the reduced transition strengths have been determined. With these first results the Tz = −3/2 nucleus 33Ar is now, together with 21Na (Tz = −1/2), the only neutron-deficient odd-A sd shell nucleus in which experimental transition strengths are available. The experimental values are compared to results of shell-model calculations which describe simultaneously mirror-energy differences and transition-strength values of mirror pairs in the sd shell in a consistent way

J. Taprogge et al.; 1 pag.; PACS numbers: 23.40.-s, 21.10.Pc, 27.60.+j, 21.60.Cs, 99.10.Cd

5 pags. ; 3 figs. ; PACS numbers: 23.40.-s, 21.10.Pc, 27.60.+j, 21.60.Cs ; Taprogge, J., et al., A low-lying state in In82131, the one-proton hole nucleus with respect to double magic Sn132, was observed by its γ decay to the Iπ=1/2- β-emitting isomer. We identify the new state at an excitation energy of Ex=1353keV, which was populated both in the β decay of Cd13183 and after β-delayed neutron emission from Cd13284, as the previously unknown πp3/2 single-hole state with respect to the Sn132 core. Exploiting this crucial new experimental information, shell-model calculations were performed to study the structure of experimentally inaccessible N=82 isotones below Sn132. The results evidence a surprising absence of proton subshell closures along the chain of N=82 isotones. The consequences of this finding for the evolution of the N=82 shell gap along the r-process path are discussed. © 2014 American Physical Society., This work was supported by the Spanish Ministerio de Ciencia e Innovación under Contracts No. FPA2009-13377-C02 and No. FPA2011-29854-C04, the Generalitat Valenciana (Spain) under grant PROMETEO/2010/101, the Japanese government under contract KAKENHI (25247045), the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. NRF- 2012R1A1A1041763), the Priority Centers Research Program in Korea (2009-0093817), OTKA contract number K-100835, the European Commission through the Marie Curie Actions call FP7-PEOPLE-2011-IEF under Contract No. 300096, the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02- 06CH11357 and the German BMBF (No. 05P12RDCIA and 05P12RDNUP) and HIC for FAIR.

Reduced transition strengths of the deexciting transitions from the first two excited states in 33Ar were measured in a relativistic Coulomb excitation experiment at the GSI Helmholtz center. The radioactive ion beam was produced by fragmentation of a primary 36Ar beam on a 9Be target followed by the selection of the reaction product of interest via the GSI Fragment Separator. The 33Ar beam hit a secondary 197Au target with an energy of approximately 145 MeV/nucleon. An array of high-purity germanium cluster detectors and large-volume BaF2 scintillator detectors were employed for γ -ray spectroscopy at the secondary target position. The Lund-York-Cologne Calorimeter was used to track the outgoing ions and to identify the nuclear reaction channels. For the two lowest energy excited states of 33Ar the reduced transition strengths have been determined. With these first results the Tz = −3/2 nucleus 33Ar is now, together with 21Na (Tz = −1/2), the only neutron-deficient odd-A sd shell nucleus in which experimental transition strengths are available. The experimental values are compared to results of shell-model calculations which describe simultaneously mirror-energy differences and transition-strength values of mirror pairs in the sd shell in a consistent way.

The four-proton hole Pd-96 neighbor of the doubly-magic Sn-100 nucleus was studied in-beam, using a fusion-evaporation reaction of a Ni-58 beam on a Sc-45 target. States of Pd-96 were established up to an excitation energy of 9707 keV. A core-excited odd-parity isomer with T-1/2 = 37.7(1.1) ns was identified. Shell model calculations were performed in four different model spaces. Even-parity states of Pd-96 are very well reproduced in large-scale shell model (LSSM) calculations in which excitations are allowed of up to five g(9/2) protons and neutrons across the N = Z = 50 gap, to the g(7/2), d(5/2), d(3/2), and s(1/2) orbitals. The odd-parity isomer can be only qualitatively interpreted though, employing calculation in the full fpg shell model space, with just one particle-hole core excitation.

We present results from stopped beam rare isotope spectroscopic investigations at the GSI (RISING) experiment based on the detection of gamma-ray transitions following the beta decay of Pd-94. A comparison between the measured low-lying level scheme of Rh-94 and the prediction from shell-model calculations reveals the important roles of the g(7/2) and g(9/2) orbitals in explaining the structural features. The low values of the Gamow-Teller strengths B(GT) can be attributed to the influence of the neutron-proton interaction, which gives rise to an increased seniority mixing for the nuclear states, thereby leading to a fragmentation of the strength to several daughter levels. These results provide further strong indications that Pd-94 resides in the middle of a structural transition region in the Pd isotopes as the N = Z line is approached.

A beta-decaying high-spin isomer in Cd-96, with a half-life T-1/2 = 0.29(-0.10)(+0.11) s, has been established in a stopped beam rare isotope spectroscopic investigations at GSI (RISING) experiment. The nuclei were produced using the fragmentation of a primary beam of Xe-124 on a Be-9 target. From the half-life and the observed gamma decays in the daughter nucleus, Ag-96, we conclude that the beta-decaying state is the long predicted 16(+) "spin-gap'' isomer. Shell-model calculations, using the Gross-Frenkel interaction and the pi nu(p(1/2,)g(9/2)) model space, show that the isoscalar component of the neutron-proton interaction is essential to explain the origin of the isomer. Core excitations across the N = Z = 50 gaps and the Gamow-Teller strength, Bd(GT) distributions have been studied via large-scale shell-model calculations using the pi nu(g, d, s) model space to compare with the experimental B(GT) value obtained from the half-life of the isomer.

Yrast states of 106Sb have been investigated in the 54Fe(58Ni,a pn) reaction using in-beam g -spectroscopic methods and in the 50Cr(58Ni,pn) reaction performing delayed g and conversion electron studies. A new isomeric state was found at 103 keV with t1/25232(21) ns. The number of states and transitions in the proposed level scheme have been doubled. The experimental results are discussed within the framework of the shell model.