Ionization in elliptically polarized pulses: Multielectron polarization effects and asymmetry of photoelectron momentum distributions

Abstract

In the tunneling regime we present a semiclassical model of above-threshold ionization with inclusion of the Stark shift of the initial state, the Coulomb potential, and a polarization induced dipole potential. The model is used for the investigation of the photoelectron momentum distributions in close to circularly polarized light, and it is validated by comparison with ab initio results and experiments. The momentum distributions are shown to be highly sensitive to the tunneling exit point, the Coulomb force, and the dipole potential from the induced dipole in the atomic core. This multielectron potential affects both the exit point and the dynamics, as illustrated by calculations on Ar and Mg. Analytical estimates for the position of the maximum in the photoelectron distribution are presented, and the model is compared with other semiclassical approaches.

Influence of permanent dipole and dynamic core-electron polarization on tunneling ionization of polar molecules

“…Our approach is simpler and has been used in Refs. [36,37,39,40,44]. Our approach would likely overestimate the core polarization at small r. Nevertheless, we will show below that our numerical results using the SAE picture are in good agreement with their data and with experiments [25].…”

“…[34,35]. Note that the effect of the dynamic core polarization was considered earlier in the context of the photoelectron momentum distribution [36]. It was also found that accounting for this effect is important for the correct reading of the attoclock experiments by Pfeiffer et al [37], even for argon.…”

“…Note that the same approach has also been used before by Shvetsov-Shilovski et al [36] and Pfeiffer et al [37] for the treatment of the photoelectron momentum distribution. Within the SAE approximation, the total dipole polarizability due to the core electrons is taken to be of the cation, as in Refs.…”

“…Within the SAE approximation, the total dipole polarizability due to the core electrons is taken to be of the cation, as in Refs. [36,37]. To avoid the singularity at r = 0 we follow Zhang et al [33] and apply a cutoff for V p in Eq.…”

Numerical investigation of the sequential-double-ionization dynamics of helium in different few-cycle-laser-field shapes

“…Specifically, we do not include the time-dependent modulation of the ionization rates induced by the oscillation of the remaining bound wave function caused by the removal of the first electron [19,21,22]. Additionally, we neglect forces between the two electrons and ions as well as between electrons [23][24][25]. However, the model reproduces the main features observed experimentally and yields a great deal of insight into the underlying dynamics.…”