Seminars Archive

Femtosecond dynamics of adsorbate resonances probed by core-hole spectroscopy

Abstract
When adsorbate core hole states are excited with photon bandwidths below their natural linewidths, the corresponding decay spectra exhibit a branching into two channels, a coherent resonant "Raman"-type channel and an incoherent "normal" Auger-type channel. In a rate description the branching ratio of the two channels can be used to extract charge transfer times for adsorbate resonances. Using adsorbates in situations of varied adsorbate-substrate coupling, I will demonstrate charge transfer times from below 1 fs up to above 70 fs for different resonances. I will also show different dependences of these times on the energetics of the resonance relative to the substrate Fermi level and discuss possible reasons for these variations.