The diffusion coefficient of a Cu adatom on the (100) surface was determined by using He-atom beam scattering as a probe. The approach relied upon measurements, in situ and in real time, of the separation between islands that nucleated on individual terraces during the sub-monolayer deposition of Cu.

H.J.Ernst, F.Fabre, J.Lapujoulade: Physical Review B, 1992, 46[3], 1929-32