distributions of photoions and photoelectrons generated in one-photon ionization in an
energy range of 300 eV≤ E γ≤ 40 keV. Our results show that for each ionization event the
photon momentum is imparted onto the photoion, which is essentially the system's center of
mass. Nevertheless, the mean value of the ion momentum distribution along the light
propagation direction is backward-directed by-3/5 times the photon momentum. These …