Partial-wave representation of the strong-field approximation. II. Coulomb asymmetry in the photoelectron angular distribution of many-electron atoms

Abstract

Strong-field ionization experiments are routinely performed with different atomic targets. While these experiments helped reveal many details about the light-matter interaction in intense laser fields, the target atoms are often modeled in a rather crude manner by neglecting most of their electronic structure. Until the present, therefore, many above-threshold ionization measurements had been understood only qualitatively, and this especially applies to the ionization with elliptically polarized laser pulses, for which the photoelectron angular distributions are known to exhibit a quite strong (Coulomb) asymmetry. This asymmetry arises from the Coulomb and short-range forces between the photoion and the outgoing field-dressed electron in the continuum. We demonstrate here how the strong-field approximation (SFA) can be combined with atomic structure theory for modeling such target-resolved observations. Using a partial-wave representation of the SFA, we show that this combination reproduces the Coulomb asymmetry for argon and xenon targets in good agreement with previous experiments and especially if a distorted-wave Volkov continuum is applied for the active electron. We therefore conclude that a better account of the initial and final electron waves in strong-field theories will enhance our understanding of ionization phenomena in intense fields.