  Ab initio calculations of the electronic energy loss of ions moving in
aluminum crystal are presented, within linear-response theory, from a realistic
description of the one-electron band-structure and a full treatment of the
dynamical electronic response of valence electrons. For the evaluation of the
density-response function we use the random-phase approximation and, also, a
time-dependent extension of local-density functional theory. We evaluate both
position-dependent and random stopping powers, for a wide range of projectile
velocities. Our results indicate that at low velocities band structure effects
slightly enhance the stopping power. At velocities just above the threshold
velocity for plasmon excitation, the stopping power of the real solid is found
to be smaller than that of jellium electrons, corrections being of about 10%.
This reduction can be understood from sum rule arguments.
