In fast collisions transfer ionization can proceed via different mechanisms:
the kinematical capture in which the ion compensates the momentum of the
captured electrons, accompanied by an independent target ionization by
an interaction of the projectile with the second electron in the target.
The electron-electron Thomas mechanism, in which the projectile knockst
one electron in a hard collision and this electron is scattered at the
other electron in the forward direction to be captured. This unique
process the continuum electron is emitted with the projectile velocity
to 90 deg while the recoiling doubly charged ion is only a spectator,
receiving very little momentum.
correlated kinematical capture in which one electron is kinematically
captured at large impact parameters while the seond electron is shaken
of due to the correlation in the initial state. This interesting
process gives a grip at a small contribution of the entangled initial
state wave function.
The figure shows that the Thomas mechanism can be clearly separated from the
other mechanisms by observing the ion momentum.
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