THE BRANDT-KITAGAWA HEAVY-ION MODEL - EMBEDDING IN THE HOMOGENEOUS ELECTRON-GAS

The ion model by Brandt and Kitagawa [Phys. Rev. B 25 (1982) 5631] has played a major role in the development of the effective charge theory for the electronic stopping of heavy ions in solids. Embedding it int o the electron gas of the target leads to an enhanced screening of its bound electrons, modification of its size parameter and eventually of its effective charge. A basic. earlier calculation [T. Kaneko, Phys. Rev. A 41 (1990) 4889] overestimates the effect, but can be improved b y confining the influence of the target dielectric to the region of th e outermost bound electrons of the ion. (C) 1997 Elsevier Science B.V.