On the sputtering yield of molecular ions

It is shown that the sputtering yield of a molecular ion can be expressed in terms of the sputtering yields of the constituent atoms, irrespective of the details of the process by which the molecular ion dissociates upon impact on the target surface. It then follows that, in general, sputtering yields on a clean surface should be about the same for molecular and atomic ions of the same mass and energy, exceptions being very light targets or very heavy projectiles, in which cases sputtering yields for molecular ions should be somewhat higher. For ions which are chemically reactive with respect to a target and thus change its surface composition, these conclusions need to be modified. Sputtering yields at very low ion energy, i.e., near the sputtering threshold, are also discussed and compared for atomic and molecular ions.