title: Real-time observation of adsorbate atom motion above a metal surface
abstract: The dynamics of cesium atom motion above the copper(111) surface following electronic excitation with light was studied with femtosecond (10(-15) seconds) time resolution. Unusual changes in the surface electronic structure within 160 femtoseconds after excitation, observed by time-resolved two-photon photoemission spectroscopy, are attributed to atomic motion in a copper-cesium bond-breaking process. Describing the change in energy of the cesium antibonding state with a simple classical model provides information on the mechanical forces acting on cesium atoms that are "turned on" by photoexcitation. Within 160 femtoseconds, the copper-cesium bond extends by 0.35 angstrom from its equilibrium value.
authors.affiliation: Advanced Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395, Japan.
authors.initials: H
authors.lastname: Petek
authors.initials: MJ
authors.lastname: Weida
authors.initials: H
authors.lastname: Nagano
authors.initials: S
authors.lastname: Ogawa