Wake potential of swift ions in solids

Abstract

Valence-electron density fluctuations are expected to form wakes trailing charged particles moving through condensed matter with velocities larger than the Bohr velocity. We compute the resulting wake potential with a quantum-mechanical dielectric response function of the electron gas which includes plasmon dispersion as well as single-particle effects at the densities of metallic conduction electrons. The binding energy of electrons trapped in this potential ranges from ∼5 eV behind protons to ∼50 eV behind heavy ions moving with kinetic energies ∼1 MeV/amu. The effects of quantum fluctuations on the binding energy and the lifetime of the wake-riding state are estimated.