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.