Based on first-order perturbation theory and the frozen-charge-state model, an analytical formula for the electronic stopping power was derived for swift lithiumlike and berylliumlike ions. The bound electrons attached to ions in the ground state were described by the Hartree-Fock-Slater determinant, in which the orbital-screening parameter in the constituent eigenfunctions was determined by the variational method. The stopping power -dE/dx for fast hydrogenlike to berylliumlike ions is found to be scaled in terms of (-dE/dx)${\mathit{Z}}_1^{\mathrm{-}\mathrm{\alpha }}$ where α ranges from 2.180 (H-like) to 2.355 (Be-like). The theoretical stopping for Li-like ions agrees quite well with the recent data on ∼10 MeV/amu ${\mathrm{O}}^{5+}$ ions.

• Received 8 December 1992

DOI:https://doi.org/10.1103/PhysRevA.49.2681