Analytical formula for the stopping power of low-energy ions in a free-electron gas

•The electronic stopping power of low-energy ions, calculated within the dielectric formalism and the Lindhard dielectric function, is revisited.•A simple and accurate analytical formula for the electronic stopping power of low-energy bare ions is proposed.•The new expression may be used together with the local-plasma approximation to predict stopping powers of ions in solids.

The electronic stopping power of a slow heavy charged particle moving through a homogeneous free-electron gas is considered within the dielectric formalism and using the Lindhard dielectric function. A simple analytical formula is proposed that is more accurate than those employed hitherto, e.g. that of Lindhard and Winther, especially for small and intermediate electron densities.