Three-body momentum exchange in ion impact ionization
Single ionization is a three-body momentum exchange process.
One can approximate it by splitting it in three separate
two-body momentum exchange processes
between projectile-electron, projectile-ion and electron-ion.
Although all three pair-wise interactions are always present,
there are paradigmatic
cases where one of the three dominates.
The figure shows the momenta of electron and ion and the momentum loss
of the projectile in the plane defined by the incoming projectile
left to right) and the scatterd projectile. At slow collisions clearly
main momentum exchange is between projectile and target, while the
is stranded with very little momentum. At fast p-He collisions in
significant momentum is exchanged in particular between projectile and
and in very fast highly charged ion collisions the main momentum
between electron and its parent ion (for more details see Moshammerxxx,
are performed at GSI by R.Moshammer(Robert.Moshammer),
J. Ullrich (Joachim.Ullrich) and collegues).