  Cross-section and neutron-emission data from heavy-ion fusion-fission
reactions are consistent with the fission of fully equilibrated systems with
fission lifetime estimates obtained via a Kramers-modified statistical model
which takes into account the collective motion of the system about the ground
state, the temperature dependence of the location and height of fission
transition points, and the orientation degree of freedom. If the standard
techniques for calculating fission lifetimes are used, then the calculated
excitation-energy dependence of fission lifetimes is incorrect. We see no
evidence to suggest that the nuclear viscosity has a temperature dependence.
The strong increase in the nuclear viscosity above a temperature of
approximately 1.3 MeV deduced by others is an artifact generated by an
inadequate fission model.
