Attosecond X-ray Chronoscopy of Core-level Photoemission

• Main Authors: Ji, Jia-Bao, Guo, Zhaoheng, Driver, Taran, Trevisan, Cynthia S, Cesar, David, Cheng, Xinxin, Duris, Joseph, Franz, Paris L, Glownia, James, Gong, Xiaochun, Hammerland, Daniel, Han, Meng, Heck, Saijoscha, Hoffmann, Matthias, Kamalov, Andrei, Larsen, Kirk A, Li, Xiang, Lin, Ming-Fu, Liu, Yuchen, McCurdy, C. William, Obaid, Razib, ONeal, Jordan T, Rescigno, Thomas N, Robles, River R, Sudar, Nicholas, Walter, Peter, Wang, Anna L, Wang, Jun, Wolf, Thomas J. A, Zhang, Zhen, Ueda, Kiyoshi, Lucchese, Robert R, Marinelli, Agostino, Cryan, James P, Wörner, Hans Jakob
• Format: Journal Article
• Language: English
• Published: 27-02-2024
• Subjects: Physics - Chemical Physics
• DOI: 10.48550/arxiv.2402.17685

Attosecond photoemission or photoionization delays are a unique probe of the
structure and the electronic dynamics of matter. However, spectral congestion
and spatial delocalization of valence electron wave functions set fundamental
limits to the complexity of systems that can be studied and the information
that can be retrieved, respectively. Using attosecond X-ray pulses from LCLS,
we demonstrate the key advantages of measuring core-level delays: the
photoelectron spectra remain atom-like, the measurements become element
specific and the observed scattering dynamics originate from a point-like
source. We exploit these unique features to reveal the effects of
electronegativity and symmetry on attosecond scattering dynamics by measuring
the photoionization delays between N-1s and C-1s core shells of a series of
aromatic azabenzene molecules. Remarkably, the delays systematically 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
wavefunction with increasing electronegativity of the 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 unravelling attosecond
electron dynamics in complex matter.