The spatial distribution of the momentum which was deposited into atomic collision cascades was considered. Particular attention was paid to the scaling and symmetry properties of this distribution. These were more complex than those of the deposited-energy density or the ion range. The use of 2 length units with differing dependences upon the recoil and ion energy was essential. This resulted in a splitting of the deposited-momentum profile into 2 contributions with differing symmetries. One of these accounted for momentum conservation, while the other represented momentum diffusion. The calculated momentum profiles exhibited excellent agreement with Monte Carlo simulation results for equivalent systems. It was recalled that the deposited momentum was known to be closely related to the anisotropy of the particle flux in a collision cascade. It was found that, while the former quantity could be expressed in terms of the latter, only approximations had been proposed for the inverse relationship. That is, an expression for the angular flux in terms of the deposited energy and momentum.

M.W.Sckerl, M.Vicanek, P.Sigmund: Nuclear Instruments and Methods in Physics Research B, 1995, 102[1-4], 86-92