BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Science enabled by MeV-UED and future opportunities DTSTART:20260707T110000Z DTEND:20260707T120000Z DTSTAMP:20260803T041300Z UID:indico-event-441@indico.xfel.eu DESCRIPTION:Speakers: Xijie Wang (Department of Physics\, Center for Synch rotron Radiation \, TU Dortmund University\,)\n\nX-ray Free Electron Laser (XFEL) revolutionized ultrafast science. One of the enabling technologies for XFEL is high-brightness electron source based on the photocathode RF gun. The MeV electrons produced by the photocathode RF gun also made it fe asible for MeV ultrafast electron diffraction [1-2]. MeV ultrafast electro n diffraction (MeV-UED) is a new paradigm of the ultrafast electron scatte ring because of its stronger diffraction and higher sensitivity to the str ucture dynamics [2]. Furthermore\, MeV electrons experience less multiple- scattering and possess “real” flat Ewald-sphere\, which make it feasib le quantitatively interpreting the physical observables and validating the oretic and simulation models. MeV-UED is an “ideal” tool to image none quilibrium and transient quantum states using total scattering technique. Science enabled by MeV-UED is broad and transformative\, it includes imagi ng fundamental photochemical processes [3-4]\, hydrogen bond dynamics in l iquid water [5]\, capturing light-induced transient states of quantum mate rials [6-8]\, tracking charge & energy transport across nano-scale heteros tructures [9-10]\, and imaging phase transformation under extreme conditio ns [11-12]. \nSimultaneous imaging of electronic and nuclear structural dy namics [13]\, together with ultrafast electron diffuse scattering [14]\, h as emerged as a next frontier for ultrafast electron scattering. The capab ility to simultaneously visualize electronic and nuclear dynamics provides a powerful approach for investigating electron–nuclear interactions in materials and chemical processes. Meanwhile\, ultrafast electron diffuse s cattering enables direct tracking of energy flow among elementary excitati ons and their mutual couplings in quantum materials.\n \n1. X.J. Wang et al\, Proceedings of the 2003 Particle Accelerator Conference\, 2003\, pp. 420-422 Vol.1\, doi:\n10.1109/PAC.2003.1288940.\n2. P Zhu et al\, “Femto second time-resolved MeV electron diffraction”\, New Journal of Physics 17 (6)\, 063004 (2014).\n3. J. Yang et al\, “Imaging CF3I conical inters ection and photodissociation dynamics with ultrafast electron diffraction ”\,\nScience 361\, 64 (2018).\n4. T. J. A. Wolf et al\,” The photochem ical ring-opening of 1\,3-cyclohexadiene imaged by ultrafast electron\ndif fraction”\, Nature Chemistry 11\, pages 504–509 (2019).\n5. J. Yang et al.\, ”Direct observation of ultrafast hydrogen bond strengthening in l iquid water”\, Nature 596\, 531–535\n(2021).\n6. E. J. Sie et al\, ” An ultrafast symmetry switch in a Weyl semimetal”\, Nature 565\,61–66( 2019).\n7. A. Kogar et al\,” Light-induced charge density wave in LaTe3 ”\, Nat. Phys.16\, 159 (2019).\n8. A. Zong et al\,”Spin-mediated shear oscillators in a van der Waals antiferromagnet”\,\nNature 620\, pages 9 88–993 (2023).\n9. D. Luo et al\, "Twist-Angle-Dependent Ultrafast Charg e Transfer in MoS2-Graphene van der Waals\nHeterostructures"\, Nano Lett. 2021\, 21\, 19\, 8051–8057.\n10. A. Sood et al\, "Bidirectional phonon e mission in two-dimensional heterostructures triggered by ultrafast charge\ ntransfer"\, Nat. Nanotechnol.18\, 29–35 (2023).\n11. M. Mo et al\, "Het erogeneous to homogeneous melting transition visualized with ultrafast ele ctron\ndiffraction"\, Science 360\, 1451 (2018).\n12. M. Mo et al\, "Ultra fast visualization of incipient plasticity in dynamically compressed matte r"\, Nat. Commun. 13\,\n(2022).\n13. J. Yang et al\, "Simultaneous observa tion of nuclear and electronic dynamics by ultrafast electron\ndiffraction "\, Science 368\, 885 (2020).\n14. T. Chase et al\, "Ultrafast electron di ffraction from non-equilibrium phonons in femtosecond laser heated Au\nfil ms"\, Appl. Phys. Lett. 108\, 41909 (2016).\n \nJoin Zoom Meetinghttps:// xfel.zoom.us/j/61017343566?pwd=5mr1XSa3aYxk0r9E9Od08ohfeclap8.1\nMeeting I D: 610 1734 3566Passcode: 430956\n\nhttps://indico.xfel.eu/event/441/ LOCATION:XHQ / E1.173 (EuXFEL) URL:https://indico.xfel.eu/event/441/ END:VEVENT END:VCALENDAR