Visualizing the Three-Dimensional Arrangement of Hydrogen Atoms in Organic Molecules by Coulomb Explosion Imaging

Journal Article · Wed Oct 01 00:00:00 EDT 2025 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/jacs.5c08730· OSTI ID:3003092

Green, Alice E. ^[1]; Chen, Keyu ^[2]; Bhattacharyya, Surjendu ^[3]; Allum, Felix ^[4]; Usenko, Sergey ^[5]; Ashfold, Michael N. R. ^[6]; Baumann, Thomas M. ^[5]; Borne, Kurtis D. ^[7]; Brouard, Mark ^[8]; Burt, Michael ^[9]; Curchod, Basile F. E. ^[6]; Erk, Benjamin ^[10]; Forbes, Ruaridh J. G. ^[11]; Ibele, Lea M. ^[12]; Ingle, Rebecca A. ^[13]; Van Sa Lam, Huynh ^[2]; Li, Xiang ^[14]; Lin, Kang ^[15]; Mazza, Tommaso ^[5]; McManus, Joseph W. ^[8] ; Meyer, Michael ^[5]; Mullins, Terence ^[5]; Figueira Nunes, Joao Pedro ^[16]; Rivas, Daniel E. ^[5]; Roerig, Aljoscha ^[5]; Rouzée, Arnaud ^[17]; Schmidt, Philipp ^[5]; Searles, John ^[2]; Senfftleben, Björn ^[18]; Stapelfeldt, Henrik ^[19]; Tanyag, Rico Mayro P. ^[19]; Trinter, Florian ^[20]; Venkatachalam, Anbu Selvam ^[2]; Wang, Enliang ^[2]; Warne, Emily M. ^[8]; Weber, Peter M. ^[21]; Wolf, Thomas J. A. ^[22]; Jahnke, Till ^[5]; Rudenko, Artem ^[2]; Boll, Rebecca ^[5]; Rolles, Daniel ^[2]

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1. Univ. of Edinburgh, Scotland (United Kingdom); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Photon Ultrafast Laser Science and Engineering Institute (PULSE); European XFEL, Schenefeld (Germany)
2. Kansas State Univ., Manhattan, KS (United States)
3. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Photon Ultrafast Laser Science and Engineering Institute (PULSE); Kansas State Univ., Manhattan, KS (United States)
4. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Photon Ultrafast Laser Science and Engineering Institute (PULSE); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
5. European XFEL, Schenefeld (Germany)
6. Univ. of Bristol (United Kingdom)
7. Kansas State Univ., Manhattan, KS (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Linac Coherent Light Source (LCLS)
8. Univ. of Oxford (United Kingdom)
9. Univ. of Oxford (United Kingdom); Trent Univ., Peterborough, ON (Canada)
10. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
11. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Linac Coherent Light Source (LCLS); Univ. of California, Davis, CA (United States)
12. Aix-Marseille Univ., Marseille (France)
13. Univ. College London (United Kingdom)
14. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Linac Coherent Light Source (LCLS)
15. Goethe Univ., Frankfurt (Germany)
16. Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Diamond Light Source, Ltd.
17. Max Born Inst., Berlin (Germany)
18. European XFEL, Schenefeld (Germany); Eidgenoessische Technische Hochschule (ETH), Zurich (Switzerland)
19. Aarhus Univ. (Denmark)
20. Fritz Haber Institute of the Max Planck Society, Berlin (Germany)
21. Brown Univ., Providence, RI (United States)
22. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Photon Ultrafast Laser Science and Engineering Institute (PULSE)

Structure-sensitive methods based on femtosecond light or electron pulses are now making it possible to measure how molecular structures change during light-induced processes. Despite significant progress, high-fidelity imaging of nuclear positions remains a challenge even for relatively small molecular systems and, notably, regarding the positions of hydrogen atoms. As demonstrated in recent work, X-ray-induced Coulomb explosion imaging (CEI) may overcome this obstacle, as its sensitivity does not depend on the mass of the imaged atoms. The photoinduced ring opening of the heterocyclic molecule 2(5H)-thiophenone has attracted recent interest. Here, in this work, we show that CEI offers a powerful route to imaging the peripheral H atoms in this molecule and thus, more generally, to tracking detailed nuclear motions (e.g., isomerizations) in organic molecules on ultrafast time scales. Specifically, we record momentum-space Coulomb explosion images that report on the three-dimensional positioning of all nuclei within the molecule, for instance, distinguishing H atoms in C–H bonds that lie within or are directed out of the plane defined by the heavy atoms. The prospect of imaging peripheral H atoms to probe photochemical dynamics is explored by coupling ab initio molecular dynamics with classical Coulomb explosion simulations, thereby differentiating potential photoproduct isomers, including those whose structures primarily differ in the position of the hydrogens.

• Research Organization: Brown Univ., Providence, RI (United States); Kansas State Univ., Manhattan, KS (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)
• Grant/Contract Number: AC02-76SF00515; FG02-86ER13491; SC0017995; SC0020276
• Other Award/Contract Number: EP/S028617/1; EP/V026690/1; EP/X026973/1; EP/Y01930X/1; ANR-20-CE29-0014; 509471550; 123-CO: 101067645; 25886; ANR-10-LABX-0039-PALM; 803718; PHYS-2409365
• OSTI ID: 3003092
• Alternate ID(s): OSTI ID: 3006414
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 41 Vol. 147; ISSN 0002-7863; ISSN 1520-5126
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
hydrogen
ions
molecular imaging
molecular structure
molecules