Time delays in correlated photoemission processes

29th International Conference on Photonic, Electronic, and Atomic Collisions

Pazourek, R.^1 ; Nagele, S.^2 ; Burgdörfer, J.^2

Department of Physics and Astronomy, Louisiana State University, Baton Rouge

LA

70803, United States^1

Institute for Theoretical Physics, Vienna University of Technology, Vienna

1040, Austria^2

关键词: Ab initio simulations;    Ejected electrons;    Photoemission process;    Relative emission;    Relative time delays;    Sequential ionization;    Two photon ionization;    Two-photon double ionization;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/635/1/012004/pdf
DOI  :  10.1088/1742-6596/635/1/012004

来源: IOP

【 摘 要 】

We theoretically study time-resolved two-photon double ionization (TPDI) of helium as probed by attosecond streaking. We review recent advances in the understanding of the photoelectric effect in the time domain and discuss the differences between one- and two-photon ionization, as well as one- and two-electron emission. We perform exact ab-initio simulations for attosecond streaking experiments in the sequential TPDI regime and compare the results to the two-electron Eisenbud-Wigner-Smith delay for the process. Our calculations directly show that the timing of the emission process sensitively depends on the energy sharing between the two outgoing electrons. In particular, we identify Fano-like interferences in the relative time delay of the two emitted electrons when the sequential ionization channel occurs via intermediate excited ionic (shake-up) states. Furthermore, we find that the photoemission time delays are only weakly dependent on the relative emission angle of the ejected electrons.