Shears mechanism in 109Cd -: art. no. 034318

Lifetimes of high-spin states in two Delta I=1 bands and one Delta I=2 band in Cd-109 have been measured using the Doppler shift attenuation method in an experiment performed using the Zr-96(O-18,5n) reaction with the GAMMASPHERE array. Experimental total angular momenta and reduced transition strengths for both Delta I=1 bands were compared with tilted axis cranking (shears mechanism) predictions and the Delta I=2 band with principal axis cranking predictions, based on configurations involving two proton g(9/2) holes and one or three valence quasineutrons from the h(11/2) and mixed g(7/2)/d(5/2) orbitals. Good overall agreement for angular momentum versus rotational frequency has been observed in each case. The Delta I=2 band is shown to have a large J((2))/B(E2) ratio suggestive of antimagnetic rotation. Additionally, both dipole bands show a decreasing trend in B(M1) strength as a function of spin, a feature of the shears mechanism. The experimental results are also compared with a semiclassical model that employs effective interactions between the proton holes and neutrons as an alternate interpretation for the shears mechanism.