Material dependence of low-velocity stopping powers

Excitations of valence electrons determine the electronic stopping power of solids for atomic projectiles moving with velocities $v_1$ so that $v_1\lesssim v_F$, where $v_F$ is the Fermi velocity of the valence electron gas. Current data vary among elements according to their position in the periodic system in agreement with new theoretical developments. A comprehensive description emerges that permits predictions of the stopping power of solids and plasmas for low-velocity ions.