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Background: One-phonon mixed-symmetry quadrupole excitations are a well-known feature of near-spherical, vibrational nuclei. Their interpretation as a fundamental building block of vibrational structures is supported by the identification of multiphonon states resulting from a coupling of fully-symmetric and mixed-symmetric quadrupole phonons. In addition, the observation of strong M1 transitions between low-lying 3- and 4+ states has been interpreted as an evidence for one-phonon mixed-symmetry excitations of octupole and hexadecapole character. Purpose: The aim of the present study is to identify collective one- and two-phonon excitations in the heaviest stable N = 52 isotone 96Ru based on a measurement of absolute Ail, E1, and E2 transition strengths. Methods: Inelastic proton-scattering experiments have been performed at the Wright Nuclear Structure Laboratory (WNSL), Yale University, and the Institute for Nuclear Physics (IKP), University of Cologne. From the acquired proton-γ and γγ coincidence data we deduced spins of excited states, y-decay branching ratios, and multipole mixing ratios, as well as lifetimes of excited states via the Doppler-shift attenuation method (DSAM). Results: Based on the new experimental data on absolute transition strengths, we identified the 2+ and 3+ members of the two-phonon mixed-symmetry quintuplet (21ms+⊙21ms+).Furthermore, we observed strong M1 transitions between low-lying 3- and 4+ states suggesting one-phonon symmetric and mixed-symmetric octupole and hexadecapole components in their wave functions, respectively. The experimental results are compared to sdg-IBM-2 and shell-model calculations. Conclusions: Both the sdg-IBM-2 and the shell-model calculations are able to describe key features of mixed-symmetry excitations of 96Ru. Moreover, they support the one-phonon mixed-symmetry hexadecapole assignment of the experimental 42+ state. [ABSTRACT FROM AUTHOR]

New positive-parity states, having a bandlike structure, were observed in 105Ru. The nucleus was produced in an induced fission reaction, and the prompt γ-rays, emitted from the fragments, were detected by the EUROBALL III multidetector array. The partial scheme of excited 105Ru levels is analyzed within the triaxial-rotor-plus-particle approach. [ABSTRACT FROM AUTHOR]

Linear polarization and angular correlations of γ-rays depopulating excited states in the neutron-deficient nucleus 9444Ru50 have been measured, enabling firm spin-parity assignments for several excited states in this nucleus. The deduced multipolarities of strong transitions in the yrast structure were found to be mostly of stretched M1, E1, and E2 types and, in most cases, in agreement with previous tentative assignments. The deduced multipolarity of the 1869 keV and the connecting 257 and 1641 keV transitions indicates that the state at 6358 keV excitation energy has spin parity 12-1 rather than 12+3 as proposed in previous works. The presence of a 12-1 state is interpreted within the framework of large-scale shell-model calculations as a pure proton-hole state dominated by the π(p-11/2⊗g-59/2) and π(p-13/2⊗g-59/2) configurations. A new positive-parity state is observed at 6103 keV and is tentatively assigned as 12+2. The 14-1 state proposed earlier is reassigned as 13-4 and is interpreted as being dominated by neutron particle-hole core excitations. The strengths of several E1 transitions have been measured and are found to provide a signature of core-excited configurations. [ABSTRACT FROM AUTHOR]

116Ru and 118Ru have been studied via β-delayed y-ray spectroscopy of nuclei produced in fragmentation reactions at the Radioactive Ion-Beam Factory (RIBF) facility. Level schemes with positive-parity states up to spin 7=6 have been constructed. The results have been discussed in terms of the interacting boson model, the algebraic collective model, and total Routhian surfaces. We conclude that the very neutron-rich nuclei still show many features associated with triaxial y-soft nuclei, represented by the 0(6) symmetry, but are approaching a spherical structure, the U(5) symmetry, with increasing neutron number towards the N = 82 shell closure. In 118Ru, hints of a shape transition in the ground state have been observed. [ABSTRACT FROM AUTHOR]

Background: The experimental study of g(I > 2) factors of nuclear states can provide information about the evolution of collectivity in certain regions of the nuclear chart, and assist in obtaining a microscopic description of the nuclear wave functions. The measurements and explanations of g{I > 2) factors are still a challenge for experiments and theory. Purpose: Measurement of the g(2+1) and g(41) factors, the latter for the first time, in the 9644Ru nucleus. Comparison of the experimental results with calculations using the shell model and collective models. Methods: The experiments made use of the transient field technique, using a Coulomb-excitation reaction in inverse kinematics. Large scale shell model calculations were performed; comparisons with previous theoretical predictions, using the tidal-wave model and the hydrodynamical model, were carried out. Results: The values of g(2+1) = +0.46(2) and g(4+-) = +0.58(8) were experimentally obtained. While the g(2+1) value agrees with the hydrodynamical model prediction of g = Z/A = +0.46. the g(4+1 ) is in agreement with the shell model predictions. The trend of the experimental g factors, as a function of nuclear spin, is not reproduced by the theoretical models discussed. Conclusions: Measurements of g(2+1 ) and g(4+1 ) in 96Ru were performed. Further theoretical efforts are necessary to explain the trend of the g factors as a function of nuclear spin for the 96Ru nucleus. Future measurements of g(4+1) should reduce the uncertainty of the result. [ABSTRACT FROM AUTHOR]

The nucleus 102Ru was studied with the GRID lifetime technique and an upper limit on the Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. of 21.6 W.u. was obtained. This nucleus is pivotal in the A ~ 100 region as it marks the boundary, in Z, between nuclei that do, and do not, become deformed with increasing neutron number, and, in N, between those that exhibit characteristics of a phase transition mediated by changes in subshell structure and those that do not. The measurements are discussed primarily in terms of vibrational structure. [ABSTRACT FROM AUTHOR]