RESUMO
Excited states in ;{152}Sm have been investigated with the ;{152}Sm(n,n;{'}gamma) reaction. The lowest four negative-parity band structures have been characterized in detail with respect to their absolute decay properties. Specifically, a new K;{pi} = 0;{-} band has been assigned with its 1;{-} band head at 1681 keV. This newly observed band has a remarkable similarity in its E1 transition rates for decay to the first excited K;{pi} = 0;{+} band at 684 keV to the lowest K;{pi} = 0;{-} band and its decay to the ground-state band. Based on these decay properties, as well as energy considerations, this new band is assigned as a K;{pi} = 0;{-} octupole excitation based on the K;{pi} = 0_{2};{+} state. An emerging pattern of repeating excitations built on the 0_{2};{+} level similar to those built on the ground state may indicate that ;{152}Sm is a complex example of shape coexistence rather than a critical point nucleus.
RESUMO
Three rotational bands in 74Kr were studied up to (in one case one transition short of) the maximum spin I(max) of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I(max). This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I = I(max).
