  We present a formalism and numerical results for the energy loss of a charged
particle scattered at an arbitrary angle from epitaxially grown multilayer
graphene (MLG). It is compared with that of free-standing graphene layers.
Specifically, we investigated the effect of the substrate induced energy gap on
one of the layers. The gap yields collective plasma oscillations whose
characteristics are qualitatively and quantitatively different from those
produced by Dirac fermions in gapless graphene. The range of wave numbers for
undamped self-sustaining plasmons is increased as the gap is increased, thereby
increasing and red-shifting the MLG stopping power for some range of charged
particle velocity. We also applied our formalism to interpret several distinct
features of experimentally obtained electron energy loss spectroscopy (EELS)
data.
