Ab initio - calculated direct and shakeup streaked photoemission spectra for helium

Understanding the correlated ionization dynamics in atoms has remained an important and challenging task [1]. By implementing an adaptive FE-DVR method to efficiently solve the two-electron time-dependent Schroedinger equation, we calculated attosecond time-resolved spectra for streaked XUV photoemission from helium. From the angle-differential calculated spectra we derived (directional) photoemission time delays between direct and 1s$^2$ $\rightarrow$ np$\epsilon$l shake-up ionization. [1] M. Ossiander et al., “Attosecond correlation dynamics” Nat. Phys. 13, 280 (2017). [2] 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).