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  • 27.50.+e  (12)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 329 (1988), S. 51-61 
    ISSN: 1434-601X
    Keywords: 27.50.+e ; 23.20.Ck ; 21.60.Ev
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High spin states in the doubly odd nucleus72Br were investigated via the reaction58Ni(16O,pn) at 52–65 MeV beam energy. A multi-element detector system consisting of ten Compton supressed Ge detectors (OSIRIS) and two NE213 neutron detectors was used to establish the yrast bands up to 5 MeV excitation energy and probable spins of 15+ resp. 14−. The lifetimes of 12 states and lifetime limits of four states were measured with the recoil distance method, among them four 0.5–3.1 ns isomers. Doppler broadened line shapes obtained in an additionalγγ-coincidence experiment via the reaction40Ca(36Ar, 3pn) at 125 MeV revealed further lifetimes and (very short) side feeding times. Three rotational bands were established with deformation parameters ¦β 2¦≈0.3 and moment of inertia parameters $$\tilde f$$ /ħ 2=36 MeV−1 (K ρ=1−) resp. 23 MeV−1; their quasi-particle configurations are being discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1434-601X
    Keywords: 21.10 R ; 23.20.Ck ; 23.20.−g ; 27.50.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The band structure of83Zr has been investigated using the Daresbury recoil separator and TESSA array with 20 Compton suppressed Ge detectors and the reaction28Si (58Ni, 2pn) at 195 MeV. DCO ratios have been used to make many new spin assignments. The three known rotational bands have been extended up to the onset of the five quasiparticle bands. On the basis of the 21/2+, 23/2+ and 25/2+ yrast and yrare states, a (3qp) structure similar to those found in the isotones79Kr and81Sr has been identified. Additional bands have been observed for the first time, one of which appears to be non-collective. Strong mixing between the various negative parity bands is evident. A multiplet of states feeding the three quasiparticle region of the negative parity yrast band has been found. The data is interpreted in the framework of the cranked shell model.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-601X
    Keywords: 21.10.HW ; 23.20.-g ; 27.50.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Deformation parameters of the positive parity yrast band and negative parity bands in83Zr are deduced from lifetimes andE2/M1 mixing ratios. Lifetimes of high spin states have been determined from recoil distance Doppler shift and Doppler shift attenuation measurements using the54Fe(32S,2pnγ) 83Zr reaction. Ten lifetimes and five lifetimes limits were determined. The positive parity band, built on theg 9/2 K=5/2 orbital has an average deformation ¦β 2¦=0.28(2), and shows a reduction ofE2 transition strengths in the observed backbend region at Iπ≈21/2+. In contrast, theE2 strengths in the negative parity states show a steady increase up to Iπ≈=15/2−. These states are more strongly deformed than the positive parity states (¦β 2¦=0.33(3)). TheE2/M1 mixing ratios show that the negative parity band hasK=3/2 and is prolate, and favour oblate deformation for the positive parity yrast band. In theK=1/2− band theE2 strength of the 7/2−→3/2− transition yields a deformation ¦β 2¦=0.26(5). The band structure is compared with calculations within the Hartree-Fock Bogoliubov cranking model.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 332 (1989), S. 397-405 
    ISSN: 1434-601X
    Keywords: 23.20.Js ; 25.40.Lw ; 27.50.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The primaryE1,M1 andE2γ-radiation in87,88,89Sr observed after thermal neutron capture was compared with the predictions of single particle and giant resonance models. The nuclei feature a wide range of neutron binding energies between 6.3 and 11.1 MeV, which makes a 5.5 MeV spectrum of primary transition energies available for investigation. The (n, γ) reaction was used to estimate the parameters of the spin-flip M1 giant resonance in strontium. The total energy weightedM1 strength of this resonance exceeds the results of shell model and random phase approximation calculations for90Zr by a factor of 3–4. TheE1 strengths were found to agree with the established giant dipole resonance model. The few data on primaryE2 transitions do not allow to differentiate between the giant quadrupole resonance and the single particle models.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-601X
    Keywords: 21.60.Cs ; 23.20.Lv ; 25.70.Jj ; 27.50.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The reaction58Ni(36Ar,α qρ)88Mo has been studied at 145 MeV beam energy. A detector array consisting of the OSIRIS spectrometer, four charged-particleΔE detectors and seven NE213 neutron detectors has been used to meaure the gamma radiation inγγ- and particle-γγ-coincidence mode. The level scheme of88Mo has been extended up to 11.6 MeV excitation energy and probable spin 23ħ; some 70 transitions and 40 levels have been identified. Spin assignments have been proposed on the basis of measured DCO ratios. Hartree Fock cranking calculations of the Total Routhians and shell model calculations of the high spin states are presented which imply near-sphericity of the yrast line up to the highest spins found. A classification of the high spin states according to their leading seniority is proposed.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1434-601X
    Keywords: 21.60.Ev ; 27.50.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Doppler shift attenuation lifetime measurements have been carried out for the 3qp and isomeric rotational bands in83Y using the reaction58Ni(28Si,3p). While the transitional quadrupole moments in the 3qp bands are slightly lower than in the 1qp bands, we found evidence for a strong reduction in ¦Qt¦ for the isomeric band.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1434-601X
    Keywords: 21.60.Ev ; 27.50.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High spin states in81Y up to the probable 33/2+ and 29/2− yrast states have been measured via the reaction58Ni(28Si,αp, using the Cologne tandem accelerator. Directional correlations of oriented nuclei were determined and the level scheme was extended with lifetimes measured by means of DSA and recoil distance techniques. Reduced transition strengths inferred from lifetimes were consistent with the results of Hartree-Fock-Bogolyubov calculations, which predict a nearly axially symmetric deformation ofβ 2≈0.37 for theπ=+ band. Predictions reveal an alignment driving the system to a smaller and triaxial deformation withβ 2=0.23 andγ=−30°, although the data show this crossing to be somewhat delayed. Particle-rotor calculations for the one-quasiparticle bands corroborate the predictions of deformation parameters based on the cranking model.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1434-601X
    Keywords: 21.10.Tg ; 21.60.Cs ; 27.50.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Lifetimes of high spin states in the threeA=89 isobars89Nb,89Mo and89Tc have been measured via the Recoil Distance Doppler Shift technique and the fusion evaporation reactions58Ni(35Cl,xnypzα) at 120 MeV beam energy. Reduced transition probabilities for about 50γ transitions were extracted. The experimental branching ratios in89Mo and reduced transition probabilities in all three isobars are compared with the predictions of the spherical shell model based on the restrictedπ(p 1/2),π(g 9/2), ν(p1/2),ν(g 9/2) configuration space with two different types of residual interaction.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1434-601X
    Keywords: 21.60.Cs ; 23.20.Lv ; 27.50.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Particle-γ andγ-coincidences of the reaction58Ni(36Ar, 4pn)89Mo have been used to gain more information about high spin states in89Mo and to establish the yrast sequence up to 7.6 MeV excitation energy and probable spin 37/2 ħ. Spins and parities were assigned on the basis of DCO-ratios measured with the OSIRIS spectrometer and a large volume Ge detector placed at 162° to the beam. Furthermore, aγ-ray angular distribution experiment was carried out using the reaction58Ni(35Cl, 3pn)89Mo. As in the neighboring isotopes88Mo and90Mo, the positive-parity high-spin states can be grouped into shell model multiplets characterized by increasing seniorities of proton particles and neutron holes in the 1g9/2 shell. The negative-parity states can be explained with one nucleon moving in thep 1/2 orbit. The energies and wave functions of these states have been deduced by means of the shell model code RITSSCHIL. The 2584 keV (21/2+) is an isomeric state the mean life of which has been estimated from delayedγγ-coincidences.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1434-601X
    Keywords: 21.60.Cs ; 27.50.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Excited states in the nucleus89Tc have been identified for the first time by measuring evaporated particle-γγ-coincidences via the fusion reaction58Ni +36Ar at 149 MeV. Nine γ-ray transitions built upon the (9/2+) ground state have been found, reaching up to a probable spin of (33/2+) at 5.3MeV excitation energy. The levels are interpreted with the shell model.
    Type of Medium: Electronic Resource
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