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From the halflife of t=3.91 (16) ns for the 2 state inSr a deformation parameter of β=0.40(1) has been derived. Within the given uncertainties, this value is equal to the recently determined β-parameters forSr andSr, indicating that in the Sr isotopes saturation of deformation is reached immediately at its onset well before neutron midshell. This behaviour is reflected by the 'twin' character ofSr andSr with identical features of their unperturbed ground-state rotational bands. These observations are discussed in terms of strong two-nucleon interactions. [ABSTRACT FROM AUTHOR]

Excited states ofSb have been investigated in theCd (Li, 4 nγ) reactions. In both level schemes, two independant parts have been exhibited with, mainly, a negative parity band based on 8 or 7 states and a positive parity sequence based on a 11 state. The interpretation of the significant levels has been performed in the core-particle model and in term of quasiparticle configurations mixing, this last approach being able to give a kind of unified description of the whole spectrum. [ABSTRACT FROM AUTHOR]

The structure of the nucleusNd is studied using theNd( d, p) reaction at a bombarding energy of 16.07 MeV. More than 80 levels are observed below 4.4 MeV excitation. Using DWBA calculations l-values and spectroscopic factors are deduced for 50 levels. Detailed calculations using a unified-model and the macroscopic-microscopic Strutinsky method are performed in order to describe the negative and positive parity states. A very good agreement with the experimental data is found. [ABSTRACT FROM AUTHOR]

The energy spectra of the N=81 nuclei have been calculated by coupling the neutron single-hole motion to the quadrupole vibrations of the nuclear surface. The wave functions are used to calculate M1 and E2 moments. Gamma-ray branching ratios are extensively discussed and compared with the many experimental data onXe,Ce andNd. Also spectroscopic factors for ( p, d) reactions have been calculated and compared to experimental single-neutron pick-up reactions. The excitation energy and the lifetime of the isomeric state π, decaying by an M4 transition, are studied, in particular in their dependence on the number of extra protons. The behaviour of the centroid of the neutron single-hole energies as a function of the number of extra protons is calculated with a delta force for the neutron-proton interaction. [ABSTRACT FROM AUTHOR]

Core polarization corrections to ground state magnetic dipole moments are calculated in first-order perturbation theory, with the use of Sussex matrix elements. These corrections are introduced in the particle-(hole-) core coupling model. It is shown that the need for effective g factors in the calculation of magnetic moments can be explained largely in terms of one-particle-one-hole polarization effects of the core. The influence of these effects on the reduced M1 transition probabilities for l-forbidden transition is also considered. [ABSTRACT FROM AUTHOR]

For single-closed shell nuclei with a large number of extra-protons, outside the Z=50, N=82 double-closed shell nucleus, a standard shell-model calculation yields dimensions of the Hamiltonian matrices beyond the scope of present computer technology. A quasi-particle (QP) calculation however, is able to describe the most important proton-excitations in a much restricted configuration space. Extended BCS+TDA calculations are performed on the single-closed shellSm andGd nuclei with a Gaussian force as effective two-body interaction. The influence of the nonconservation of the exact number of extra-protons in the BCS-approach is studied by performing a projection onto the states with an exact number of extra-protons (BCS+P). The first excited 2, 4 and 6 states inGd are described mainly by the (1 g7/2) (2 d5/2) $$(1h11/2)_{J^\pi }^2 $$ configuration. [ABSTRACT FROM AUTHOR]

Levels inRh have been investigated via the γ -rays following the β-decay of 2.1 sRu. The Ru activity was produced in the fission ofCf and separated chemically from the fission product mixture. The emitted γ-rays were studied by γ singles and γ(t) coincidence measurements. Evidence for intruder states inRh has been obtained. Their properties are discussed and compared with those in the lighter Rh isotopes. [ABSTRACT FROM AUTHOR]