[Zurück]

R. Pazourek, J. Feist, S. Nagele, E. Persson, B. I. Schneider, L. A. Collins, J. Burgdörfer:
"Ultrafast two-electron dynamics in helium";
Vortrag: COST WG1 meeting, Han-sur-Lesse, Belgium; 12.04.2010 - 16.04.2010.

With the advent of intense and controllable vuv and xuv light sources, the study of multiphoton processes and electron dynamics in atoms has come within experimental reach. For theoretical studies, helium is virtually the only multi-electron atom which can be solved numerically without approximations for the electron-electron interaction. Therefore it serves as an important test atom for the understanding of more complex atoms and simple molecules.
The first part of the talk will be about two-photon double ionization (TPDI) which, depending on the photon energy, can occur either sequentially or nonsequentially. Those two processes leave a clear signature in the energy and angular differential electron distributions, as well as in the recoil ion momentum distribution. By using attosecond xuv pulses, the two separated stages of the sequential process are confned to within a short time interval of each other. This allows the study of dynamical electron correlations in this regime.
In the second part I will talk about streaking of shake-up ionization in helium. The question is whether there is a time delay between electrons liberated from an atom with or without shake-up excitation of the remaining ion and if such an apparent "time delay" can be extracted using XUV-IR streaking setups.

attosecond, helium, photoionization