Attosecond Delays in X-ray Molecular Ionization
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.
Cite
@article{arxiv.2402.12764,
title = {Attosecond Delays in X-ray Molecular Ionization},
author = {Taran Driver and Miles Mountney and Jun Wang and Lisa Ortmann and Andre Al-Haddad and Nora Berrah and Christoph Bostedt and Elio G. Champenois and Louis F. DiMauro and Joseph Duris and Douglas Garratt and James M. Glownia and Zhaoheng Guo and Daniel Haxton and Erik Isele and Igor Ivanov and Jiabao Ji and Andrei Kamalov and Siqi Li and Ming-Fu Lin and Jon P. Marangos and Razib Obaid and Jordan T. O'Neal and Philipp Rosenberger and Niranjan H. Shivaram and Anna L. Wang and Peter Walter and Thomas J. A. Wolf and Hans Jakob Wörner and Zhen Zhang and Philip H. Bucksbaum and Matthias F. Kling and Alexandra S. Landsman and Robert R. Lucchese and Agapi Emmanouilidou and Agostino Marinelli and James P. Cryan},
journal= {arXiv preprint arXiv:2402.12764},
year = {2024}
}