Collective and single-particle degrees of freedom in 104Ru

Abstract A previous multiple Coulomb excitation experiment on 104 Ru using 208 Pb projectiles has been extended to larger scattering angles by bombarding a thin 208 Pb target with a 4.6 MeV/u 104 Ru beam. A new experimental set-up allowed pγγ triple coincidences and pγ directional correlations to be measured, which could be used to extend the level scheme up to I π = 10 + in the ground-state band and I π = 8 + in the γ-band. Corresponding intraband and interband B (E2) values and static quadrupole moments for the ground-state band are deduced from the combined information of the two experiments and the collective structure is discussed in the framework of different collective models. Both the level energies of the 10 + member of the ground-state band and of the 8 + member of the γ-band deviate considerably from what is expected for unperturbed rotational bands. To explain these irregularities observed at higher spins, calculations within the triaxial cranked shell model have been performed.