SPIN-DEPENDENT TRIAXIAL DEFORMATION IN NEUTRON-RICH MO ISOTOPES

The Eurogam-2 array has been used to study gamma rays emitted followin g the spontaneous fission of a Cm-248 source. Analysis of Doppler-broa dened line shapes corresponding to decays from excited rotational stat es in neutron-rich Sr, Zr, and Mo fission fragments has enabled the fi rst measurements of state lifetimes in these nuclei at around I = 10. The results are consistent with a predicted rotation-induced change in the triaxiality of the yrast states of the Mo isotopes that contrasts with the more stable behavior observed in the Zr and Sr nuclei.