  We re-calculate electron yields and stopping power of protons colliding with
surfaces of NaCl-type insulators. In this article, the projectile is considered
to move taking into account the static and polarization potentials with all the
individual ions forming the surface lattice unlike our previous work (Phys.
Rev. A 75, 042904 (2007)) where the projectile was considered to move in an
homogeneous planar potential. Substantial differences (up to forty percent of
increment) have been found especially when the projectile incident angle
approaches the critical one. We compare our prediction for electron yield and
stopping power with the available experimental data for LiF, KI and KCl.
