TRANSITION STRENGTHS IN NB-86 AND ZR-86

Mean lifetimes of states in Nb-86 and Zr-86 produced by the Ni-58(S-32 ,3pn)Nb-86 and Ni-58(S-32,4p)Zr-86 reactions at 130 MeV have been meas ured using the recoil-distance method. The B(E2) strength of 11(2) W.u . for the 8(+)-->6(+) transition in Nb-86 implies weak collectivity at low excitation energies for the pi=+ yrast band. The weak dipole tran sition strength of the 8(+)-->7 decay suggests that the configuration for the 7 (h) over bar state is different from that of the other yrast states. In general, the B(E2) rates obtained for transitions in Zr-86 agree with those previously published, thus supporting the suggestion of a weakly collective structure based on shell-model excitations at low energies. Hartree-Fock-Bogolyubov cranking calculations indicate a spherical shape for low-spin vacuum configuration states in Zr-86. [S 0556-2813(98)02405-4].