ON THE TREATMENT OF LIGHT-ION ELECTRONIC STOPPING IN DENSE MATTER

A review is given on single-electron mechanisms and the corresponding theoretical approaches describing the electronic energy-transfer proce sses of light ions in gases and solids. Special emphasis is given to a discussion on the connection between exact Bloch-wave treatments and free-atom approximations. In the case of solids, perturbation theory i s applied to the stopping of low-energy ions in the alkaline metals Li and Na. These calculations include Bloch wavefunctions of the Wigner- Seitz type obtained from a Hartree-Fock-Slater calculation and allow f or a prediction of the mean energy loss under channeling conditions. R esults of the most widely used local-density approximation are compare d to data of our more complete perturbative treatment. Comparison is a lso made with recent LCAO calculations.