Time-resolved ultrafast x-ray scattering from an incoherent electronic mixture.
Time-resolved ultrafast x-ray scattering from photo-excited matter is an emerging method to image ultrafast dynamics in matter with atomic-scale spatial and temporal resolutions. For a correct and rigorous understanding of current and upcoming imaging experiments, we present the theory of time-resolved x-ray scattering from an incoherent electronic mixture using quantum electrodynamical theory of light-matter interaction. We show that the total scattering signal is an incoherent sum of the individual scattering signals arising from different electronic states and therefore heterodyning of the individual signals is not possible for an ensemble of gas-phase photo-excited molecules. We scrutinize the information encoded in the total signal for the experimentally important situation when pulse duration and coherence time of the x-ray pulse are short in comparison to the timescale of the vibrational motion and long in comparison to the timescale of the electronic motion, respectively. Finally, we show that in the case of an electronically excited crystal the total scattering signal imprints the interference of the individual scattering amplitudes associated with different electronic states and heterodyning is possible.
Publisher URL: http://arxiv.org/abs/1711.00156
Researcher is an app designed by academics, for academics. Create a personalised feed in two minutes.
Choose from over 15,000 academics journals covering ten research areas then let Researcher deliver you papers tailored to your interests each day.
Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.