Hamburg 2009 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 22: Attosecond Physics II

A 22.2: Vortrag

Mittwoch, 4. März 2009, 17:00–17:15, VMP 8 R208

Laser-Assisted Photoemission from surface/adsorbate systems — •Guido Saathoff¹, Luis Miaja-Avila², Stefan Mathias³, Jing Yin², Chan La-o-vorakiat², Michael Bauer⁴, Martin Aeschlimann³, Margaret Murnane², and Henry Kapteyn² — ¹MPI für Quantenoptik, Garching — ²Jila and University of Colorado, Boulder, CO — ³TU Kaiserslautern — ⁴Universität Kiel

Laser-assisted photoemission (LAPE) and Auger decay (LAAD) have evolved into a powerful tool for time-resolved studies of the femtosecond-to-attosecond dynamics of highly-excited states in atoms. Recently we have extended LAPE to clean solid surfaces [1] and a detailed study has allowed the discrimination of surface-LAPE against adverse above-threshold photoemission (ATP) caused by the high laser intensities required for dressing [2]. This has led to the first direct time-resolved observation of the lifetime of a core-excited state of an atom adsorbed onto a surface. By combining LAPE with LAAD, we measured the 4d⁻¹ core level lifetime of Xenon on Pt(111) to be 7± 1 fs [3]. We also show that using longer laser wavelengths enhances LAPE and LAAD while ATP is strongly suppressed. This will allow for time-resolved measurements on low-energy Auger electrons, which are usually buried by ATP. Our results open up time domain measurements of electronic processes in surface/adsorbate systems, which are fundamental to the understanding of surface chemistry.
[1] L. Miaja-Avila et al.,Phys Rev. Lett. 97, 113604 (2006)
[2] G. Saathoff et al., Phys. Rev. A, 77, 022903 (2008)
[3] L. Miaja-Avila et al., Phys.Rev. Lett., 101, 046101 (2008)