Time delays for attosecond streaking in photoionization of neon

Abstract

We revisit the time-resolved photoemission in neon atoms as probed by attosecond streaking. We calculate streaking time shifts for the emission of 2p and 2s electrons and compare the relative delay as measured in a recent experiment by Schultze et al. [Science 328, 1658[Science 328, (2010]. The B-spline R-matrix method is employed to calculate accurate Eisenbud-Wigner-Smith time delays from multielectron dipole transition matrix elements for photoionization. The additional laser field-induced time shifts in the exit channel are obtained from separate, time-dependent simulations of a full streaking process by solving the time-dependent Schrödinger equation on the single-active-electron level. The resulting accurate total relative streaking time shifts between 2s and 2p emission lie well below the experimental data. We identify the presence of unresolved shake-up satellites in the experiment as a potential source of error in the determination of streaking time shifts.

Real-Time Probing of Electron Dynamics Using Attosecond Time-Resolved Spectroscopy

“…An isolated sub-200-as pulse at 106 eV ionizes neon atoms, and the emitted electrons are streaked by a few-cycle near-infrared pulse, resulting in a remarkable delay measured to be 21 ± 5 as in the photoemission of a 2s electron relative to a 2p electron in neon (64). Multiple theoretical efforts were performed to understand the origin of the measured photoemission delay (73)(74)(75)(76)(77)(78) and have thus far underpredicted the observed delay by approximately a factor of two. Possible reasons proposed for this discrepancy include the interaction of the atoms with the streaking field, along with contributions from shake-up satellites and many-electron correlations.…”

Attosecond chronoscopy of photoemission

“…The situation is strikingly different for many-electron atoms. First experiments were performed for rare gas atoms (Schultze et al, 2010;Klünder et al, 2011;Guénot et al, 2012), the results of which have led to a flurry of theoretical investigations (Schultze et al, 2010;Kheifets and Ivanov, 2010;Komninos et al, 2011;Nagele et al, 2011Nagele et al, , 2012Nagele et al, , 2014Baggesen and Madsen, 2011;Zhang and Thumm, 2010;Ivanov and Smirnova, 2011;Dahlström et al, 2012bDahlström et al, , 2013Dahlström et al, , 2012aPazourek et al, 2012a,b;Śpiewanowski and Madsen, 2012;Pazourek et al, 2013;Moore et al, 2011;Carette et al, 2013;Kheifets, 2013;Dixit et al, 2013;Feist et al, 2014;Saha et al, 2014;Wätzel et al, 2015). Yet, satisfactory agreement between theory and experiment is still outstanding and many open questions remain.…”

Two-electron processes in multiple ionization under strong soft-x-ray radiation

“…The relevant cross section is about 0.02 Mb, whereas the cross section for the primary channel is essentially 1 Mb, confirming that ionization plus excitation per fine structure pair of channels amounts to a few percent of the primary process. In a more recent paper on neon [28], considerably larger contributions of shake-up processes have been noted. To the best of our knowledge, nothing is known about the corresponding cross sections for the ions, which implied we should proceed on the basis of some estimates.…”