Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Symposium: Beyond Optical Wavelengths: Time-Resolved Spectroscopy of Surface Dynamics with EUV and XUV Radiation I (Invited Speakers: Reinhard Kienberger, Martin Aeschlimann)

O 58.4: Vortrag

Donnerstag, 28. Februar 2008, 10:45–11:00, HE 101

Surface spectroscopy of CO/Pt(111) with High Harmonics in the XUV — •Thorben Haarlammert¹, Sebastian Wegner¹, Grigorius Tsilimis¹, Helmut Zacharias¹, and Alexander Golovin² — ¹Physikalisches Institut, Westfälische Wilhelms-Universität, Münster — ²Institute of Physics, St. Petersburg State University

We report on the generation of High Harmonic radiation in the photon energy range up to 100 eV with up to 10 kHz repetition rate, based on the conversion of femtosecond Ti:sapphire radiation in rare gases. The fundamental laser is based on a single stage, multiple pass ampli-fication of a cavity-dumped oscillator. Output pulse energies of 1 mJ and pulse durations of les than 30 fs at adjustable repetition rates up to 10 kHz are achieved. The generated High Harmonics are separated by a toroidal grating and directed to the surface. A time-of-flight detector with multiple anodes registers the kinetic energies of emitted photoelectrons. The angular distributions of photoelectrons emitted form CO/Pt(111) under s-polarized excitations have been measured for a variety of initial photon energies. Different from gas phase results a significant intensity of photoelectrons are emitted also in the normal direction, i.e., in the direction of the C - O chemical bond. A first theoretical investigation supports qualitatively the observed angular distributions.