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X-ray laser-induced time-of-flight photoelectron spectroscopy

X-ray laser induced time-of-flight photoelectron spectroscopy has been used to probe the core-level and valence band electronic structure of room-temperature bulk materials with picosecond time resolution. The LLNL COMET compact tabletop x-ray laser source provides the necessary high photon flux, high energy, monochromaticity, picosecond pulse duration, and coherence for probing ultrafast changes in the chemical and electronic structure of these materials. Valence band and core-level spectra were recorded for transition metal surfaces. In situ sputter etching with Ar ions at 30° incidence will be implemented to improve the surface purity and consequently increase core-level and valence-band photoemission intensity. This work demonstrates a powerful new technique for probing reaction dynamics and for probing changes of local order on surfaces on their fundamental timescales. Future work will include the study of fundamental phenomena such as non-thermal melting, chemical bond formation, intermediate reaction steps, and the existence of transient reaction products.