  A survey is presented of various aspects of the interaction of charged
particles with solids. In the framework of many-body perturbation theory, we
study the nonlinear interaction of charged particles with a free gas of
interacting electrons; in particular, nonlinear corrections to the stopping
power are analyzed, and special emphasis is made on the separate contributions
that are originated in the excitation of either electron-hole pairs, single
plasmons, or double plasmons. Ab initio calculations of the electronic energy
loss of ions moving in real solids are also presented, and the energy loss of
charged particles interacting with simple metal surfaces is addressed.
