Nonlinear calculations of the stopping power for slow hydrogen and helium projectiles in solids

The stopping powers for slow H and He projectiles in different solids are calculated using density-functional theory with local density approximation for exchange correlations in the scattering potential and the concept of local plasma density approximation for excitation channels. The calculated results for the stopping power ratio $R=(1/4)\mathrm{}\left[\right(-{dE/dx)}_{\mathrm{He}}/\left(-{dE/dx)}_{\mathrm{H}}\right]$ in some solids are in agreement with recent experimental predictions.