Ultrafast Electron Dynamics Following Ionization

Alexander Kuleff
Theoretische Chemie
Physikalisch-Chemisches Institut
Universit├Ąt Heidelberg
Im Neuenheimer Feld 229
D-69120 Heidelberg, Germany

About ten years ago it was shown theoretically that after a sudden ionization
the electronic many-body effects alone can beget rich ultrafast electron dynamics.
The positive charge created after the ionization can migrate throughout the system
on a femtosecond time scale solely driven by the electron correlation and electron
relaxation. Although typical for the inner-valence ionized states, it appeared only
recently that this charge migration phenomenon can also take place after
ionization out of the outer-valence shell. The ab initio method for multielectron
wave-packet propagation developed for treating electron dynamics following
ionization will be presented. The approach is equally suitable for tracing in real
time and space the electron dynamics of both decaying and non-decaying
electronic states. Results from calculations on different systems will be presented
and the mechanisms underlying the charge migration will be analyzed in terms of
simple models. The possibilities for experimental verification of the phenomenon
will also be discussed. In particular, it will be shown that the charge migration may
produce a measurable IR radiation.