Abstract

We calculated ab initio attosecond time-resolved spectra for streaked XUV photoemission (PE) from helium. For the n = 2 shake-up channel, we find PE time-delays relative to direct [He⁺ (n = 1)] PE in agreement with the experimental and calculated results of Ref. [1]. In addition, we provide relative PE delays for n = 3 shake-up. Within a multipole expansion and by comparing our ab initio results for angle-resolved spectra with a simplified single-active-electron calculation, we examine the contributions of the lowest multipole orders of the residual He⁺(n = 2,3) charge distributions on the PE delay.

© 2023 The Author(s)