Tuesday, October 18, 2022 - 3:30pm

Abstract: Electron motion is a key ingredient of chemical reactions and is also the means by which light energy is harnessed in photochemistry. The natural timescale for such electronic motion is typically in the range of tens to hundreds of attoseconds in small molecular systems. Consequently, the study of ultrafast electronic phenomena requires the generation of laser pulses shorter than 1 fs, and of sufficient intensity to interact with their target with high probability. Free Electron Lasers (FELs), such as the Linac Coherent Light Source (LCLS), are now able to achieve these conditions, allowing for the probing of electron dynamics on this natural time scale, elucidating the earliest processes involved in chemical change.

In this talk, I will present our first results demonstrating nonlinear spectroscopies such as pump/probe spectroscopy, and X-ray wave mixing using this unique source. We demonstrated the preparation of a coherent electronic wavepacket by driving stimulated X-ray Raman scattering. Combing attosecond X-ray pulses with an external laser field we are able to time-resolve the photoemission dynamics of core-level electrons in molecules.

Speaker: 

James Cryan

Institution: 

Stanford University

Location: 

RH 104