학술논문
Attosecond Delays in X-ray Molecular Ionization
Document Type
Working Paper
Author
Driver, Taran; Mountney, Miles; Wang, Jun; Ortmann, Lisa; Al-Haddad, Andre; Berrah, Nora; Bostedt, Christoph; Champenois, Elio G.; DiMauro, Louis F.; Duris, Joseph; Garratt, Douglas; Glownia, James M.; Guo, Zhaoheng; Haxton, Daniel; Isele, Erik; Ivanov, Igor; Ji, Jiabao; Kamalov, Andrei; Li, Siqi; Lin, Ming-Fu; Marangos, Jon P.; Obaid, Razib; O'Neal, Jordan T.; Rosenberger, Philipp; Shivaram, Niranjan H.; Wang, Anna L.; Walter, Peter; Wolf, Thomas J. A.; Wörner, Hans Jakob; Zhang, Zhen; Bucksbaum, Philip H.; Kling, Matthias F.; Landsman, Alexandra S.; Lucchese, Robert R.; Emmanouilidou, Agapi; Marinelli, Agostino; Cryan, James P.
Source
Subject
Language
Abstract
The photoelectric effect is not truly instantaneous, but exhibits attosecond delays that can reveal complex molecular dynamics. Sub-femtosecond duration light pulses provide the requisite tools to resolve the dynamics of photoionization. Accordingly, the past decade has produced a large volume of work on photoionization delays following single photon absorption of an extreme ultraviolet (XUV) photon. However, the measurement of time-resolved core-level photoionization remained out of reach. The required x-ray photon energies needed for core-level photoionization were not available with attosecond tabletop sources. We have now measured the x-ray photoemission delay of core-level electrons, and here report unexpectedly large delays, ranging up to 700 attoseconds in NO near the oxygen K-shell threshold. These measurements exploit attosecond soft x-ray pulses from a free-electron laser (XFEL) to scan across the entire region near the K-shell threshold. Furthermore, we find the delay spectrum is richly modulated, suggesting several contributions including transient trapping of the photoelectron due to shape resonances, collisions with the Auger-Meitner electron that is emitted in the rapid non-radiative relaxation of the molecule, and multi-electron scattering effects. The results demonstrate how x-ray attosecond experiments, supported by comprehensive theoretical modelling, can unravel the complex correlated dynamics of core-level photoionization.