Atomic ionization by a sudden momentum transfer

We present a theoretical study of the distributions of ejected electrons as a result of the ionization of a hydrogen atom by a sudden momentum transfer. We show that the Coulomb-Volkov distorted wave theory in the impulsive limit reproduces the exact solution of the time dependent Schroedinger equation. The validity of the strong field approximation is also probed. We show that whereas classical and quantum momentum distributions right after a kick are identical, pronounced differences arise during the subsequent electron-nucleus interaction for weak momentum transfers.