title: Differences between thermal and laser-induced diffusion.
abstract: A combination of femtosecond laser excitation with a low-temperature scanning tunneling microscope is used to study long-range interaction during diffusion of CO on Cu(111). Both thermal and laser-driven diffusion show an oscillatory energy dependence on the distance to neighboring molecules. Surprisingly, the phase is inverted; i.e., at distances at which thermal diffusion is most difficult, it is easiest for laser-driven diffusion and vice versa. We explain this unexpected behavior by a transient stabilization of the negative ion during diffusion as corroborated by ab initio calculations.
authors.affiliation: Leibniz Universität Hannover, Institut für Festkörperphysik, Abteilung für atomare und molekulare Strukturen (ATMOS), Appelstrasse 2, D-30167 Hannover, Germany.
authors.forename: Ch
authors.initials: Ch
authors.lastname: Zaum
authors.affiliation: Leibniz Universität Hannover, Institut für Festkörperphysik, Abteilung für atomare und molekulare Strukturen (ATMOS), Appelstrasse 2, D-30167 Hannover, Germany.
authors.forename: K M
authors.initials: KM
authors.lastname: Meyer-Auf-der-Heide
authors.affiliation: Leibniz Universität Hannover, Institut für Festkörperphysik, Abteilung für atomare und molekulare Strukturen (ATMOS), Appelstrasse 2, D-30167 Hannover, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Mehlhorn
authors.affiliation: Departement of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: S
authors.initials: S
authors.lastname: McDonough
authors.affiliation: Departement of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: W F
authors.initials: WF
authors.lastname: Schneider
authors.affiliation: Ruhr-Universität Bochum, Lehrstuhl für physikalische Chemie I, D-44780 Bochum, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Morgenstern