  We investigate collision dynamics involving two electrons and a quantum dot
embedded in a quantum wire. One electron is initially at rest in the ground
state of the dot, whereas the other electron is incident on the dot with a
rather well defined velocity. Excitation, reflection and transmission
probabilities are obtained by resolving the dynamics explicitly. Also, the
probability of both electrons being unbound after collision is studied. It is
found that the dynamics is strongly influenced by the presence of doubly
excited states; reflection becomes considerably more probable in the energetic
vicinity of such states. This, in turn, contributes to an increase in the
probability of trapping also the second electron within the dot.
