Abstract The condensation of single atoms on a Lennard-Jones fee (111) plane has been studied by molecular dynamics to probe the factors affecting transient diffusion. Condensing atoms are found to localize rapidly, primarily because of the efficient transfer of energy during the first impact. Subsequent behavior is dictated by the exact point of impact. Head-on collisions with surface atoms are less effective than collisions at binding sites, as the rebound energy returned to the adatom after the first impact is larger. A new picture of the condensation mechanism, in terms of the correlation between point of impact, rebound energy, and mobility is presented.