  The coupled-channel theory is a natural way of treating nonelastic channels,
in particular those arising from collective excitations characterized by
nuclear deformations. A proper treatment of such excitations is often essential
to the accurate description of experimental nuclear-reaction data and to the
prediction of a wide variety of scattering observables. Stimulated by recent
work substantiating the near validity of the adiabatic approximation in
coupled-channel calculations for scattering on statically deformed nuclei, we
explore the possibility of generalizing a global spherical optical model
potential (OMP) to make it usable in coupled-channel calculations on this class
of nuclei. To do this, we have deformed the Koning-Delaroche global spherical
potential for neutrons, coupling a sufficient number of states of the ground
state band to ensure convergence. We present an extensive study of the effects
of collective couplings and nuclear deformations on integrated cross sections
as well as on angular distributions for neutron-induced reactions on statically
deformed nuclei in the rare-earth region. We choose isotopes of three
rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors,
to exemplify the results of the proposed method. Predictions from our model for
total, elastic and inelastic cross sections, as well as for elastic and
inelastic angular distributions, are in reasonable agreement with measured
experimental data. These results suggest that the deformed Koning-Delaroche
potential provides a useful regional neutron optical potential for the
statically deformed rare earth nuclei.
