Long-range scattering of electrons by electron-hole pair excitations at metal surfaces

The low-energy regime (0.1-0.3 eV) of the electron-energy-loss spectrum from a clean Cu(100) surface has been measured. The experimental data show excellent agreement with predictions from a jellium calculation of the response function g(q,ω). The weak inelastic signal derives from long-range excitation of electron-hole pairs; the surface potential and the spatial variation of the potential from the probing electron are the ′ momentum sources. © 1983 The American Physical Society.