Femtosecond dynamics of the model-like adsorption system Cs/Cu(111) is probed by two-photon photoelectron spectroscopy (2PPE) using phase-modulated (chirped) laser pulses. The experimental data are quantitatively modeled within a wavepacket propagation approach under explicit consideration of the adsorbate motion. The results enable us to assign characteristic chirped-pulse 2PPE features to the ultrafast adsorbate dynamics associated with the excited state lifetime and the adsorbate motion, and to improve on the qualitative interpretation of experimental data as published in Petek et al. [J. Phys. Chem. A 104, 10234 (2000)]. Our results show that nonlinear photoemission with a chirped pulse in a single-pulse scheme can complement real-time studies based on pump-probe schemes to gain quantitative insights into the femtosecond dynamics of ultrafast surface processes.

• Received 18 June 2010

DOI:https://doi.org/10.1103/PhysRevB.82.165430