Photoelectron – ion entanglement in streaked direct and shake-up photoemission from helium: an ab initio approach*

We applied our FE-DVR code for the ab initio calculation of single- and double-ionization of gaseous helium atoms [1] to explore the effects of electronic correlation on attosecond time- and angle-resolved photoemission. Our calculated spectra and relative photoemission time delays for IR streaked direct and He+ (n=2) shake-up XUV emission agree well with experimental and theoretical data in [2]. To scrutinize the influence of the transient induced oscillating residual excited He+ (n=2,3) charge distribution, we compared our ab-initio streaking calculations with single active electron (SAE) calculations. By adjusting effective multipole SAE potentials to ab initio calculated He+* charge distributions, we assessed to role of individual multipole components of the residual He+* ion on spectra and photoemission delays.

[1] A. Liu and U. Thumm, “Laser-assisted XUV double ionization of helium: Energy-sharing dependence of joint angular distributions”, Phys. Rev. A 91, 043416 (2015).

[2] M. Ossiander et al., “Attosecond correlation dynamics” Nat. Phys. 13, 280 (2017).