Attosecond X-Ray Core-Level Chronoscopy of Aromatic Molecules

Journal Article · Fri Nov 14 00:00:00 EST 2025 · Physical Review. X

DOI:https://doi.org/10.1103/dp5w-qxqc· OSTI ID:3013756

Ji, Jia-Bao ^[1]; Guo, Zhaoheng ^[2]; Driver, Taran ^[3]; Trevisan, Cynthia S. ^[4]; Cesar, David ^[3]; Cheng, Xinxin ^[3]; Duris, Joseph ^[3]; Franz, Paris L. ^[3]; Glownia, James ^[3]; Gong, Xiaochun ^[5]; Hammerland, Daniel ^[1]; Han, Meng ^[6]; Heck, Saijoscha ^[1]; Hoffmann, Matthias ^[3]; Kamalov, Andrei ^[3]; Larsen, Kirk A. ^[3]; Li, Xiang ^[3]; Lin, Ming-Fu ^[3]; Liu, Yuchen ^[7]; McCurdy, C. William ^[7] ; Obaid, Razib ^[3]; O’Neal, Jordan T. ^[3]; Rescigno, Thomas N. ^[8]; Robles, River R. ^[3]; Sudar, Nicholas ^[3]; Walter, Peter ^[3]; Wang, Anna L. ^[3]; Wang, Jun ^[3]; Wolf, Thomas J. A. ^[3]; Zhang, Zhen ^[3]; Ueda, Kiyoshi ^[9]; Lucchese, Robert R. ^[8]; Marinelli, Agostino ^[3]; Cryan, James P. ^[3]; Wörner, Hans Jakob ^[1]

---

1. Eidgenoessische Technische Hochschule (ETH), Zurich (Switzerland)
2. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Ecole Polytechnique Federale Lausanne (EPFL) (Switzerland)
3. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
4. Cal Poly Maritime Academy, Vallejo, CA (United States)
5. Eidgenoessische Technische Hochschule (ETH), Zurich (Switzerland); Zhejiang Univ., Hangzhou (China)
6. Eidgenoessische Technische Hochschule (ETH), Zurich (Switzerland); Kansas State Univ., Manhattan, KS (United States)
7. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Univ. of California, Davis, CA (United States)
8. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
9. Eidgenoessische Technische Hochschule (ETH), Zurich (Switzerland); Tohoku Univ., Sendai (Japan); ShanghaiTech Univ. (China)

Attosecond photoemission or photoionization delays are a unique probe of the structure and the electronic dynamics of matter. However, the spectral congestion of valence photoelectron spectra sets fundamental limits to the complexity of systems that can be studied, and the delocalization of valence electron wave functions blurs the spatial origin of the photoelectron wave packet. Using attosecond x-ray pulses from LCLS, we demonstrate the key advantages of measuring core-level delays: The photoelectron spectra remain atomlike, the measurements become element specific, and the observed scattering dynamics originate from a pointlike source when multicenter interference effects are negligible. We exploit these unique features to reveal the effects of changing functional groups (C-H vs N) and symmetry on attosecond scattering dynamics by measuring and calculating the photoionization delays between N−1⁢𝑠 and C−1⁢𝑠 core shells of a series of aromatic azabenzene molecules. Remarkably, the delays increase with the number of nitrogen atoms in the molecule and reveal multiple resonances. We identify two previously unknown mechanisms regulating the associated attosecond dynamics, namely the enhanced confinement of the trapped wave function with the replacement of C-H groups by N atoms and the decrease of the coupling strength among the photoemitted partial waves with increasing symmetry. This study demonstrates the unique opportunities opened by measurements of core-level photoionization delays for unraveling attosecond electron dynamics in complex matter.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC02-05CH11231; AC02-76SF00515
• OSTI ID: 3013756
• Journal Information: Physical Review. X, Journal Name: Physical Review. X Journal Issue: 4 Vol. 15; ISSN 2160-3308
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English