Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 29: Zeitaufgelöste Spektroskopie II

O 29.2: Vortrag

Donnerstag, 27. März 2003, 11:30–11:45, FOE/ORG

Time resolved bichromatic two-photon photoemission - numerical simulation based on a density-matrix approach — •Dorothea Hoffmann, Michael Bauer, Joerg Lange, Felix Steeb, and Martin Aeschlimann — Kaiserslautern University of Technology, 67663 Kaiserslautern

In the last decade, time-resolved two-photon photoemission (TR-2PPE) has been used by many groups in order to investigate the lifetime of excited electronic states on pure and adsorbate covered surfaces. In general, time-resolved calculation are carried out to simulate the measured auto (or cross)correlation trace in order to extract the relaxation time of the investigated intermediate state. In a bichromatic 2PPE experiment two intermediate state at different energies are simultaneously probed resulting in a asymmetric crosscorrelation trace. In the case of equal occupation of both probed intermediate states, the reconvolution method based on the Liouville-von-Neumann-equations becomes very time consuming. We developed a noval matlab-based fitting routine which describes the motion of the density matrix elements of the excited four level system by means of eight parameters. The program considerably decreased the necessary computing time to extract the two different investigated electronic lifetimes.