THEORY OF THE DIRECT AND INDIRECT FORCES FOR A SINGLE IMPURITY ATOM IN THE ELECTRON-GAS

The force exerted on a single impurity atom in a uniform electron gas (bulk jellium) due to an applied ac electric field is discussed based on first-principles calculations within time-dependent density-functional theory. It is shown that the indirect (electron-wind) force is related with the impurity resistivity by the same equation as in the classical theory. The effective charge for the direct force varies between ∼0 and the bare ionic charge, depending sensitively on the electron density of the host metal. © 1995 The American Physical Society.