  A survey is presented of current investigations of the impact of band
structure effects on various aspects of the interaction of charged particles
with real solids. The role that interband transitions play in the decay
mechanism of bulk plasmons is addressed, and results for plasmon linewidths in
Al and Si are discussed. {\it Ab initio} calculations of the electronic energy
loss of ions moving in Al and Si are also presented, within linear response
theory, from a realistic description of the one-electron band structure and a
full treatment of the dynamic electronic response of valence electrons. Both
random and position-dependent stopping powers of valence electrons are
computed.
