title: Direct measurement of core-level relaxation dynamics on a surface-adsorbate system.
abstract: The coupling between electronic states in a surface-adsorbate system is fundamental to the understanding of many surface interactions. In this Letter, we present the first direct time-resolved observations of the lifetime of core-excited states of an atom adsorbed onto a surface. By comparing laser-assisted photoemission from a substrate with a delayed Auger decay process from an adsorbate, we measure the lifetime of the 4d(-1) core level of xenon on Pt(111) to be 7.1+/-1.1 fs. This result opens up time-domain measurements of surface dynamics where energy-resolved measurements may provide incomplete information.
authors.affiliation: JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA. Luis.Miaja-Avila@colorado.edu
authors.forename: L
authors.initials: L
authors.lastname: Miaja-Avila
authors.forename: G
authors.initials: G
authors.lastname: Saathoff
authors.forename: S
authors.initials: S
authors.lastname: Mathias
authors.forename: J
authors.initials: J
authors.lastname: Yin
authors.forename: C
authors.initials: C
authors.lastname: La-o-vorakiat
authors.forename: M
authors.initials: M
authors.lastname: Bauer
authors.forename: M
authors.initials: M
authors.lastname: Aeschlimann
authors.forename: M M
authors.initials: MM
authors.lastname: Murnane
authors.forename: H C
authors.initials: HC
authors.lastname: Kapteyn