Journal Article

PUBDB-2025-04823

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Imaging Valence Electron Rearrangement in a Chemical Reaction Using Hard X-Ray Scattering

Gabalski, I. (Corresponding author)Extern* ; Green, A. ; Lenzen, P. ; Allum, F.Extern*DESY* ; Bain, M. ; Bhattacharyya, S. ; Britton, M. A. ; Champenois, E. G. ; Cheng, X. ; Cryan, J. P. ; Driver, T. ; Forbes, R. ; Garratt, D. ; Ghrist, A. M. ; Graßl, M. ; Kling, M. F. ; Larsen, K. A. ; Liang, M. ; Lin, M.-F. ; Liu, Y. ; Minitti, M. P. ; Nelson, S. ; Robinson, J. S. ; Bucksbaum, P. H. ; Wolf, T. J. A.Extern*XFEL.EU* ; List, N. H. ; Glownia, J. M.

2025
APS College Park, Md.

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Please use a persistent id in citations: doi:10.1103/53h3-vykl  doi:10.3204/PUBDB-2025-04823

Abstract: We have observed the signatures of valence electron rearrangement in photoexcited ammonia using ultrafast hard x-ray scattering. Time-resolved x-ray scattering is a powerful tool for imaging structural dynamics in molecules because of the strong scattering from the core electrons localized near each nucleus. Such core-electron contributions generally dominate the differential scattering signal, masking any signatures of rearrangement in the chemically important valence electrons. Ammonia represents an exception to the typically high core-to-valence electron ratio. We measured 9.8 keV x-ray scattering from gas-phase deuterated ammonia following photoexcitation via a 200 nm pump pulse to the 3s Rydberg state. We observed changes in the recorded scattering patterns due to the initial photoexcitation and subsequent deuterium dissociation. Ab initio calculations confirm that the observed signal is sensitive to the rearrangement of the single photoexcited valence electron as well as the interplay between adiabatic and nonadiabatic dissociation channels. The use of ultrafast hard x-ray scattering to image the structural rearrangement of single valence electrons constitutes an important advance in tracking valence electronic structure in photoexcited atoms and molecules.

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Contributing Institute(s):

1. FS-FLASH (FS-FLASH)

Research Program(s):

1. 631 - Matter – Dynamics, Mechanisms and Control (POF4-631) (POF4-631)

Experiment(s):

1. Measurement at external facility

Appears in the scientific report 2025

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Electronics and Telecommunications Collection ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; Nationallizenz ; SCOAP3 sponsored Journal ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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