Abstract

An electron in front of a metal surface experiences the long-range image force. In the Coulomb-like potential an infinite series of bound hydrogenic states with energies E., ≅ − 0.85 eV/n² below the vacuum level can exist for many low-index surfaces. These image potential states have been studied extensively by inverse photo emission and two-photon pho-toemission (2PPE) because they represent a particularly fundamental class of surface states whose wave functions are localized at the surface and decay exponentially into the bulk.¹

© 1997 Optical Society of America