Angle-resolved time delays for shake-up ionization of helium

Stefan Donsa, Manuel Ederer, Renate Pazourek, Joachim Burgdörfer, and Iva Březinová

Phys. Rev. A 102, 033112 – Published 21 September 2020

Abstract

Recent angle-resolved experiments using reconstruction of attosecond bursts by interference of two-photon transitions (RABBITT) have shown that the photoionization time delay depends on the emission angle of the photoelectron. In this paper we demonstrate that for photoemission from helium accompanied by shake-up (correlation satellites) the angular variation of the time delay is dramatically enhanced by the dipolar coupling between the photoelectron and the highly polarizable residual ion in the IR field. We show that the additivity rule for the time delays due to the atomic potential, the continuum-continuum coupling by the IR field, and due to this two-electron process remains valid for angle-resolved RABBITT. Our results are expected to be also applicable to other multielectron systems that are highly polarizable or feature a permanent dipole moment.