89Y(3He,t) reaction at 25 MeV

Nineteen angular distributions were obtained for the 89Y(3He,t) 89Zr reaction at 25 MeV. The angular distribution of the 0.59-MeV state, thought previously to be the antianalog state, is characterized by L = 2 with spin-flip. This indicates the presence of a configuration, other than the antianalog configuration, in the wave function of the 0.59-MeV state. Arguments are presented to show that the g9/2 → g9/2 transition with L = 2, S = 1 is responsible for the excitation of this state. Angular distributions leading to the ground state, the 1.514-, 2.784-, and 2.932-MeV states are very similar. Since the ground state and the 1.514-Mev state have J/sup pi/ = 9/2+, this suggests that the other states also have J/sup pi/ = 9/2+. The angular distribution leading to the ground state was not satisfactorily fitted by distorted-wave calculations, since the forward peaking corresponded to L = 2, rather than to the allowed L = 3 and L = 5. The structure of the 9/2+ states was investigated in terms of the coupling of a g9/2 neutron hole to the 0+ states in 90Zr