  The microscopic description of nuclear fission still remains a topic of
intense basic research. Un- derstanding nuclear fission, apart from a
theoretical point of view, is of practical importance for energy production and
the transmutation of nuclear waste. In nuclear astrophysics, fission sets the
upper limit to the nucleosynthesis of heavy elements via the r-process. In this
work we initiated a systematic study of intermediate energy proton-induced
fission using the Constrained Molecu- lar Dynamics (CoMD) code. The CoMD code
implements an effective interaction with a nuclear matter compressibility of
K=200 (soft EOS) with several forms of the density dependence of the
nucleon-nucleon symmetry potential. Moreover, a constraint is imposed in the
phase-space occu- pation for each nucleon restoring the Pauli principle at each
time step of the collision. A proper choice of the surface parameter of the
effective interaction has been made to describe fission. In this work, we
present results of fission calculations for proton-induced reactions on : a)
232 Th at 27 and 63 MeV, b) 235 U at 10, 30, 60 and 100 MeV, and c) 238 U at
100 and 660 MeV. The calculated observables include fission-fragment mass
distributions, total fission energies, neutron multiplicities and fission
times. These observables are compared to available experimental data. We show
that the microscopic CoMD code is able to describe the complicated many-body
dynamics of the fission process at intermediate and high energy and give a
reasonable estimate of the fission time scale. Sensitivity of the results to
the density dependence of the nucleon symmetry potential (and, thus, the
nuclear symmetry energy) is found. Further improvements of the code are
necessary to achieve a satisfactory description of low energy fission in which
shell effects play a dominant role.
