Ab initio - calculated streaked and angle-resolved direct and shake-up photoemission spectra for helium

Understanding the correlated ionization dynamics in atoms has remained a challenging task. By implementing an adaptive FE-DVR method to efficiently solve the two-electron time-dependent Schrödinger equation, we calculated ab initio attosecond time-resolved spectra for streaked XUV photoemission from helium. For the n=2 shake-up channel, we find photoemission time-delays relative to direct photoemission in agreement with the experimental and calculated results of Ossiander et al. [Nature Phys 13, 280 (2017)] and provide relative photoemission delays for the n=3 shake up channel. We also examine the contributions of the lowest multipole orders of the residual He⁺ (n=2,3) charge distributions and effect of the residual dipole-laser coupling on the shakeup streaking delay.