  The coupled-channel technique augments a non-relativistic distorted wave born
approximation scattering calculation to include a coupling to virtual states
from the negative energy region. It has been found to be important in low
energy nucleon-nucleus scattering. We modify the nucleon-nucleus standard
optical potentials, not designed for a coupled-channel space, so they can be
used in that setting. The changes are small and systematic. We use a standard
scattering code to adjust a variety of optical potentials and targets such that
the original fit to scattering observables are maintained as we incorporate the
coupled-channel environment. Overall over forty target nuclei were tested from
$A=12$ to $A=205$ and nucleon projectile energies from 1 MeV to 200 MeV. There
is excellent improvement in fitting the scattering observables, especially for
low energy neutron scattering.The corrections were found to be unimportant for
projectile energies greater than 200 MeV. The largest changes are to the
surface amplitudes while the real radii and the real central amplitude are
modified by only a few percent, every other parameter is unchanged. This
technique is general enough to be applied to a variety of inelastic theoretical
calculations.
