  We construct nucleonic microscopic optical potentials by combining the
Green's function approach with the coupled-cluster method for $\rm{^{40}Ca}$
and $\rm{^{48}Ca}$. For the computation of the ground-state of $\rm{^{40}Ca}$
and $\rm{^{48}Ca}$, we use the coupled-cluster method in the
singles-and-doubles approximation, while for the A = $\pm 1$ nuclei we use
particle-attached/removed equation-of-motion method truncated at
two-particle-one-hole and one-particle-two-hole excitations, respectively. Our
calculations are based on the chiral nucleon-nucleon and three-nucleon
interaction $\rm{NNLO_{sat}}$, which reproduces the charge radii of $^{40}$Ca
and $^{48}$Ca, and the chiral nucleon-nucleon interaction $\rm{NNLO_{opt}}$. In
all cases considered here, we observe that the overall form of the neutron
scattering cross section is reproduced for both interactions, but the imaginary
part of the potential, which reflects the loss of flux in the elastic channel,
is negligible. The latter points to neglected many-body correlations that would
appear beyond the coupled-cluster truncation level considered in this work. We
show that, by artificially increasing the parameter $\eta$ in the Green's
function, practical results can be further improved.
