Ultrafast X-ray scattering as a probe of quantum dynamics

by Adam Kirrander (School of Chemistry, University of Edinburgh, UK)

Tuesday 24 May 2016, 10:00 → 11:00 Europe/Stockholm

FB54

New x-ray free-electron lasers such as the LCLS and the XFEL provide ultrashort bursts of intense X-rays that can be used to study processes in matter with temporal and spatial resolution. One important goal is to follow the motion of atoms during photochemical reactions. Recently we recorded the first time-resolved ultrafast X-ray scattering signal for a benchmark gas-phase reaction, the electrocyclic ring-opening reaction of 1,3- cyclohexadiene, at the LCLS [1]. A key aspect of the data analysis and the interpretation of the experiments was accurate ab-initio quantum molecular dynamics simulations based on the multiconfigurational Ehrenfest method [2,3]. We will discuss the simulations used to analyse the experiments, but also the general theoretical framework for the analysis of ultrafast X-ray scattering experiments, including inelastic effects. Prospects for investigating electron dynamics and other non-stationary states will also be touched upon [4]. [1] M. P. Minitti et al., Phys. Rev. Lett. 114, 255501 (2015). [2] A. Kirrander et al., J. Chem. Theory Comput., 12, 957 (2016). [3] C. C. Pemberton et al., J. Phys. Chem. A 119, 8832 (2015). [4] H. Suominen et al., Phys. Rev. Lett. 112, 043002 (2014).