Abstract

Time-resolved photoelectron spectroscopy is a key tool for the investigation of the photoinduced molecular dynamics on ultrashort time scales. In order to resolve the different details of the ultrafast photochemical processes, the generation and further improvement of ultrashort ultraviolet (UV) and extreme-ultraviolet (XUV) pulses is of great relevance. In this work, we present a UV pump - XUV probe beamline with sub-20 fs temporal resolution, unambiguously characterized by an in-situ photoelectron cross-correlation measurement. The extreme temporal resolution allows us to fully track the S₂/S₁ passage in acetylacetone (AcAc), resolving for the first time the ultrashort lifetime of the S₂ state.

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