  Shaking (shakeup + shakeoff) probabilities accompanying ion-atom collisions
are studied using hydrogenic wavefunctions for K-, L-, M- shell electrons in
the sudden approximation limit. The role of recoil velocity in the shaking
processes is discussed. Further, it is found that the suddenness of collision
between projectile and target nuclei plays a major factor in shaking of
respective atomic system than the recoil of nuclei.
