  The transformation of an atomic nucleus into two excited fission fragments is
modeled as a strongly damped evolution of the nuclear shape, until scission
occurs at a small critical neck radius, at which point the mass, charge, and
shape of each fragment are extracted. The available excitation energy then is
divided statistically on the basis of the microscopic level densities. This
approach takes account of the important (and energy-dependent) finite-size
effects. After the fragments have been fully accelerated and their shapes have
relaxed to their equilibrium form, they undergo sequential neutron evaporation.
The dependence of the resulting mean neutron multiplicity on the fragment mass,
$\bar{\nu}$(A), including the dependence on the initial excitation energy of
the fissioning compound nucleus, is in good agreement with the observed
behavior, as demonstrated here for $^{235}$U(n,f).
