2019/07/02 by Daniel Hammerland, D. Hammerland, Hammerland, D. +34
Chemistry · Physics and Astronomy · #Advanced Chemical Physics Studies #Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Laser-Matter Interactions and Applications #Mass Spectrometry Techniques and Applications #physics.atom-ph
paper · pdf · doi:10.48550/arxiv.1907.01219
arxiv created 2019/07/02 · openalex publication_date 2019/07/02 · arxiv updated 2019/07/03 · openalex created_date 2019/07/12 · openalex updated_date 2026/07/28
Attosecond photoionization delays have mostly been interpreted within the single-particle approximation of multi-electron systems. The strong electron correlation between the photoionization channels associated with the 3p and 3s orbitals of argon presents an interesting arena where this single-particle approximation breaks down. Around photon energies of 42~eV, the 3s photoionization channel of argon experiences a ``Cooper-like" minimum, which is exclusively the result of inter-electronic correlations with the 3p shell. Photoionization delays around this ``Cooper-like" minimum have been predicted theoretically, but experimental verification has remained a challenge since the associated photoionization cross section is inherently very low. Here, we report the measurement of photoionization delays around the Cooper-like minimum that were acquired with the 100~kHz High-Repetition 1 laser system at the ELI-ALPS facility. We report relative photoionization delays reaching up to unprecedented values of 430 +/- 20~as, as a result of electron correlation. Our experimental results are in partial agreement with state-of-the-art theoretical results, but also demonstrate the need for additional theoretical developments.