Strong-field triple ionization of atoms with $p^3$ valence shell

Abstract

The interaction of strong pulsed femtosecond laser field with atoms having three equivalent electrons in the outer shell (p 3 configuration, e.g. nitrogen) is studied via numerical integration of a time-dependent Schrödinger equation on a grid approach. Single, double and triple ionization yields originating from a completely antisymmetric wave function are calculated and extracted using a restricted-geometry model with the soft-core potential and three active electrons. The direct triple ionization channel is found to produce a larger yield than the channel connected with single and then direct double ionization. Compared against earlier results investigating the ns 2 np 1 configuration, we propose that the differences found here might in fact be accessible through electron's momentum distribution.

Three-electron correlations in strong laser field ionization: Spin induced effects

“…In the case of Neon, however, there is a single "zero" bisector in the Dalitz plots of the 8-plot set, thus it does not survive rotations and additions provided to obtain the "experimental" spinaveraged plot. The observed difference in Dalitz plots for Neon and Nitrogen is in line with recalled suppression of correlated escapes for the case of Nitrogen [41]. At the same time both the N and Ne plots share a common feature: a qualitative change of Dalitz plot structures around the field amplitude F = 0.1 a.u.…”

“…For atoms with fully antisymmetric wavefunction in their ground state the channels involving any kind of simultaneous escape (either the double ionization in the mixed triple ionization or the direct triple ionization) are suppressed in comparison to the sequential ionization channel. For atoms with a partially antisymmetric wavefunction, however, the mixed ionization channel is not suppressed [41]. Basing on the fact that in the case of two-electron events the non-sequential ionization manifest its correlated character on the electron's momentum distributions in a form of the famous finger-like structures [62,63], we expect to recognize indications of correlated motion in Dalitz plots as well.…”

“…Its power is of particular importance for studies of recollisional dynamics induced by IR femtosecond laser pulses. In particular, different double ionization channels of multi-electron atoms (affecting different electrons) cannot be resolved in a two-electron coincidence experiment [40]; the three-electron coincidence scheme, on the other hand, potentially could allow one to track the relative contributions of different channels [41].…”

“…Recently, we presented introductory studies of strongfield triple ionization, however, due to the intrinsic complexity of the problem, inevitably we restricted ourselves to only investigate the dependence of ionization yields on the laser pulse amplitude [40,41,51,52]. In the present work, we raise the analysis to a significantly higher level, addressing three electrons momenta distributions.…”

“…Results: In order to show the capabilities of an anticipated coincidence experiment on triple strong-field ionization, we simulated the dynamics within three-activeelectron models of Nitrogen and Neon atoms -the examples of systems with spatially fully antisymmetric wavefunction and with partially antisymmetric wavefunction, correspondingly. These two models were previously studied in the context of the ionization yield dependence on the laser field amplitude [40,41,51,52]. In essence the results are as follows.…”