  The effects of short-range correlations on the nucleon self-energy in
$^{40}$Ca are investigated using the charge-dependent Bonn (CDBonn)
interaction. Comparisons are made with recent results for the self-energy of
$^{40}$Ca derived from the dispersive optical-model (DOM). Particular emphasis
is placed on the non-locality of the imaginary part of the microscopic
self-energy which suggests that future DOM analyses should include this
feature. In particular, data below the Fermi energy appear sensitive to the
implied orbital angular momentum dependence of the self-energy. Quasiparticle
properties obtained for the CDBonn interaction are substantially more
mean-field-like than the corresponding DOM results with spectroscopic factors
larger by about 0.2 e.g. Reaction cross sections obtained from the microscopic
self-energy for scattering energies up to 100 MeV indicate that an adequate
description of volume absorption is obtained while a considerable fraction of
surface absorption is missing. The analysis of the non-locality of the
imaginary part of the microscopic self-energy suggests that a simple gaussian
provides an adequate description, albeit with rather large values for $\beta$,
the non-locality parameter.
