Journal Article

PUBDB-2025-04490

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Shake-Down Spectroscopy as State- and Site-Specific Probe of Ultrafast Chemical Dynamics

Thompson, H. J. ; Bonanomi, M. ; Pedersen, J. ; Plekan, O. ; Pal, N. ; Grazioli, C. ; Prince, K. C. ; Tenorio, B. N. C. ; Devetta, M. ; Faccialà, D. ; Vozzi, C. ; Piseri, P. ; Danailov, M. B. ; Demidovich, A. ; Brynes, A. D. ; Simoncig, A. ; Zangrando, M. ; Coreno, M. ; Feifel, R. ; Squibb, R. J. ; Holland, D. M. P. ; Allum, F. ; Rolles, D.Extern* ; Decleva, P. ; Schuurman, M. S. ; Forbes, R. ; Coriani, S. (Corresponding author)CFEL*Extern*DESY* ; Callegari, C. ; Minns, R. S. (Corresponding author)Extern*XFEL.EU* ; Di Fraia, M. (Corresponding author)Extern*

2025
ACS Publications Washington, DC

This record in other databases:  

Please use a persistent id in citations: doi:10.1021/jacs.5c09162  doi:10.3204/PUBDB-2025-04490

Abstract: Tracking the multifarious ultrafast electronic and structural changes occurring in a molecule during a photochemical transformation is a challenging endeavor that benefits from recent experimental and computational progress in time-resolved techniques. Measurements of valence electronic states, which provide a global picture of the bonding structure of the molecule, and core electronic states, which provide insight into the local environment, traditionally require different approaches and are often studied separately. Here, we demonstrate that X-ray pulses from a seeded free-electron laser (FEL) enable the measurement of high-resolution, time-resolved X-ray photoelectron spectra (XPS) that capture weak satellite states resulting from shake-down processes in a valence-excited molecule. This approach effectively combines the advantages of both valence- and core-state investigations. We applied this method to investigate photoexcited CS2 molecules, where the role of internal conversion (IC) and intersystem crossing (ISC) in determining the predissociation dynamics is controversial. We present XPS spectra from photoexcited CS2, obtained at the FERMI FEL. High-resolution measurements, compared to the corresponding spectra obtained from accurate multireference quantum chemical calculations, reveal that shake-down satellite channels are highly sensitive to both valence electronic and geometric changes. Previous studies of the predissociation dynamics have led to uncertain assignments of the branching between singlet and triplet excited states. We derive a propensity rule that demonstrates the spin-selectivity of the shake-downs. This selectivity allows us to unequivocally assign contributions from the bright and dark singlet excited states, with populations tracked along the predissociation dynamic pathway.

Note: CUI: Advanced Imaging of Matter

---

Contributing Institute(s):

1. FS-CFEL-3 (CFEL-DESYT)

Research Program(s):

1. 631 - Matter – Dynamics, Mechanisms and Control (POF4-631) (POF4-631)
2. Ex-Net-0002-Phase2-3 - Advanced Imaging of Matter: Structure, Dynamics and Control on the Atomic Scale - AIM (2018_Ex-Net-0002-Phase2-3) (2018_Ex-Net-0002-Phase2-3)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2025

---

Database coverage:
; ; ; BIOSIS Previews ; Biological Abstracts ; Chemical Reactions ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 15 ; Index Chemicus ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

---