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Adam Kirrander
Senior Lecturer, University of Edinburgh, UK
Visiting Scientist, Brown University, USA

Adam Kirrander is an expert on the application of new light and electron sources for imaging of atoms and molecules in real time. He has chaired several international meetings, including two Faraday Discussions (2016/2021) and is currently editor of a special issue of Journal of Physics B. He has contributed book chapters on topics such as quantum dynamics and ultrafast scattering and published more than 70 articles, including in journals such as Nature Chemistry, Nature Communications, and Proceedings of the National Academy of Sciences. He was selected as a finalist in the Falling Walls 2020 science festival and he and his collaborators were awarded the 2021 Horizon Prize for their work on ultrafast scattering by the Royal Society of Chemistry.

Adam received his first MSc degree from Uppsala University, in biophysics, followed by an MSc and DPhil in theoretical chemistry from University of Oxford. He was a postdoc at University College London and a Marie Curie fellow at Laboratoire Aimé Cotton in Paris. Following a stint at the Institute for Theoretical AMO Physics at Harvard-Smithsonian in Boston, he moved to Edinburgh in 2012. Although primarily a theoretician, Adam has a keen interest in interacting with experiments and the experimental community. He has played a critical role in conceiving, carrying out, and analysing pioneering x-ray scattering experiments. In several instances, his theoretical work has driven the development of novel techniques and methods. Web page: http://www.kirrander.chem.ed.ac.uk

Molecular structure and dynamics from ultrafast x-ray scattering

Adam Kirrander^§, School of Chemistry, University of Edinburgh, United Kingdom

Currently at: Swedish Collegium for Advanced Studies, Uppsala, Sweden

The exponential growth of molecular structures in the Cambridge Structural Database and the Protein Data Bank is testament to the importance of the concept of structure in chemistry. New X-ray Free-Electron Lasers (XFELs) are making it possible to determine not only average structures, but also the dynamic changes in atomic positions that underpin molecular function. Ultrafast x-ray scattering at X-ray Free-Electron Lasers (XFELs) provides a remarkable window onto ultrafast photochemical and photophysical processes. We will review recent experimental advances that include the mapping of atomic motions during a chemical reaction,¹ the nascent science of excited-state structure determination,2 and observation of nearly-instant changes in electron density upon photoexcitation.3 We will investigate how scattering cross-sections, crucial for the interpretation of experiments, can be calculated and the physical insights gained from different types of scattering.^4-6 Strikingly, the distinction between structural dynamics, on one hand, and spectroscopy, on the other, becomes increasingly blurred. This points towards future developments that may include the direct characterization of electronic states and electron correlation.^5-6

References

¹M. P. Minitti et al. Physical Review Letters 114 255501 (2015)

2B. Stankus et al. Nature Chemistry 11 716 (2019)

3H.W. Yong et al. Nature Communications 11 2157 (2020)

4A. Kirrander et al. Journal of Chemical Theory and Computations 12 957 (2016)

5N. Zotev et al. Journal of Chemical Theory and Computations 16 2594 (2020)

6M. Simmermacher et al. Physical Review Letters 122 073003 (2019)

^§Adam.Kirrander@ed.ac.uk

http://www.kirrander.chem.ed.ac.uk