This model was based upon molecular dynamics simulations and explained, in a realistic manner, the high activation energies and pre-exponential factors which were typically observed at homologous temperatures of more than about 0.7. The model was based upon adatom-vacancy pair formation on terraces, and was expected to be applicable to a wide range of solids.

I.I.Suni, E.G.Seebauer: Surface Science Letters, 1994, 301[1-3], 235-8