Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 60: Poster Session III (Methods: Atomic and electronic structure; Methods: electronic structure theory; Methods: Molecular simulations and statistical mechanics; Methods: Sanning probe techniques; Methods: other (experimental); Methods: other (theory) )

O 60.27: Poster

Mittwoch, 24. März 2010, 17:45–20:30, Poster B2

Chirped Pulse Two Photon Photoemission technique to study adsorbate dynamics — •Marianne Bader, Indranil Sarkar, Felix Steeb, Andreas Ruffing, and Martin Aeschlimann — Department of Physics, University of Kaiserslautern, 67663 Kaiserslautern, Germany

Time resolved Two Photon Photoemission (TR 2PPE) is a well-known method in surface physics to study adsorbate dynamics. However, it's temporal resolution is limited by the Heisenberg uncertainty principle. Here we propose a novel method to observe dynamics of adsorbate states using Chirped Pulse Two Photon Photoemission (CP 2PPE). This method utilizes a suitable modified spectral phase of the exciting femtosecond laser pulse, modulated by a Fork prism pair [1]. We apply this technique in the case of Cs/Cu(111), where we observe significant energy shifts of the excited adsorbate state (Cs*) as well as a peak broadening. The obeserved asymmetry in peak position is suggestive of possible adsorbate motion [2]. We further propose to apply the method of CP 2PPE to systems with shorter time constants where time resolved methods are restricted.

[1] R. L. Fork et al, Opt. Lett. 9 (1984) 150

[2] F. Steeb, PhD Thesis, TU Kaiserslautern, 2008