No abstract available

No abstract available

[en] The level scheme of ₉₃Ru has been studied in ₄₀Ca induced reactions on Ni and Fe targets. Two new levels feeding the known 17/2⁺ state have been established: an isomeric level (Tsub(1/2)=2.6 μs) at 2081.5 keV with J=21/2⁺ and a level at 2103 keV, presumably a 17/2^- state. The B(E2; 21/2⁺->17/2⁺) value and the level scheme are compared to shell model predictions. (orig.)

[en] Recently few low-lying energy levels of the N=49 nuclei ⁹²Tc, ⁹¹Mo and ⁹³Ru have been observed. A simple shell model calculation has been done for these nuclei assuming (π gsub(9/2)sup(n)) (νgsub(9/2)sup(-1)) configuration. The necessary interaction was derived empirically from the spectra of ⁹²Mo and ⁹⁰Nb. The calculated binding energies and the spectra are in good agreement with the observed ones. In ⁹³Ru some high spin states are predicted which are not yet observed. (author)

[en] Shell model calculations for the nuclei ⁹¹Mo, ⁹²Tc and ⁹³Ru in the Talmi approach have been done. The ground state binding energies and the excitation spectra agree with experiment. (author)

[en] Short communication. 1 ref., 1 fig., 1 tab

[en] The g-factors and half lives of three isomers in the N=49 nucleus ⁹³Ru and the N=50 nucleus ⁹⁵Rh were measured using the PAD method. The results are: ⁹³Ru; Isup(π) = 21/2⁺: g = 0.850(2), tsub(1/2) = 2.6(3) μs, Isup(π) = 17/2^-: g = 0.51(2), tsub(1/2) = 35(4) ns, ⁹⁵Rh; Isup(π) = 17/2^-: g = 1.28(4), tsub(1/2) = 19(1) ns. The g-factors are discussed within the shell model and with respect to M1 core polarization and mesonic effects. (Auth.)

[en] The projectile-target system ⁴⁰Ca+⁵⁸Ni has been used to produce the neutron deficient N=49 isotones ⁹²Tc, ⁹³Ru, ⁹⁴Rh, and ⁹⁵Pd. The multidetector array NORDBALL including particle selection was used. The yrast level scheme could in three cases be determined up to and above spin values corresponding to the highest angular momenta attainable in the previously used configuration spaces for shell model calculations. The yrast level schemes of the N=49 isotones bear a striking relationship to those of the corresponding N=50 isotones. By interpreting the experimental high spin yrast structure in shell model configurations we hope to facilitate the choice of a restricted configuration space to be used for calculations. Generally, there is an intrinsic simplicity in most of the observed yrast or near-yrast states

[en] The N=49 isotones ⁸⁸Y, ⁸⁹Zr, ⁹⁰Nb, ⁹¹Mo, ⁹²Tc and ⁹³Ru are studied in the framework of the shell model with valence nucleons occupying the 2psub(1/2) and 1gsub(9/2) single-particle levels. The residual proton-neutron effective interaction is determined by a least-squares fit to the experimental energies of states in these nuclei with well established spins and parities. The effects of requiring the effective interaction to conserve seniority and model-space isospin are examined. It is found that the existing body of experimental data is consistent with conservation of T=1 seniority but that the data call for small isospin mixing that can be traced to model-space truncation effects. The resulting shell-model wave functions are used to calculate energy levels, single-nucleon spectroscopic factors and electromagnetic transition rates. These model wave functions also provide a basis for a qualitative discussion of the weak coupling multiplet structure that persists in the low-lying states of all of these nuclei. In general, all observed properties of yrast levels and analog states are well reproduced by the model as are the positions of many non-yrast levels. Within this model space unique O⁺ anti-analog states emerge in ⁸⁸Y, ⁹⁰Nb and ⁹²Tc, but the 9/2⁺ and 1/2^- anti-analogs are highly fragmented in the even-Z nuclei. (Auth.)

[en] Static magnetic dipole and electric quadrupole moments of nuclear isomers were measured using secondary beam techniques. The isomers were produced by heavy-ion fusion evaporation reactions and formed into secondary beams by the Rochester recoil mass spectrometer (RMS). These isomer beams were oriented and stopped in a perturbing environment. Perturbed angular distributions of the isomers' decay radiations were observed to extract the nuclear moments. Three distinct studies were made using variations of this general technique. The preservation, following separation by the RMS, of reaction-induced nuclear alignment for Ar-like ⁶⁰Ge and Ne-like ₅₄Fe ions was established. The degree of alignment observed is estimated to be roughly 25% of the initial alignment. Electric quadrupole moments of polarized ⁹²Mo(8⁺) and ⁹³Ru(21/2⁺) isomers were measured. The sign of Q_92Mo was found to be negative, indicating that the state is of a proton particle rather than hole character. Q_93Ru was found to be +0.03(1)b. This result is consistent with the isomer's small B(E2,21/2⁺ → 17/2⁺) but is not well predicted by shell-model calculations. The third experiment, which has not yet been completed, is an application of the β-NMR technique to a measurement of the magnetic dipole moment of ²³Mg. A preliminary result of |μ_23Mg| = 0.536(13) μ_N has been obtained