Formulae for Solid-on-Solid Nucleation Model

The solid-on-solid model, with nearest- and next-nearest neighbour interactions, of two-dimensional nucleation on the surface of a crystal in unstable equilibrium with its supersaturated vapour allows from the local mean direction of curved step to derive closed formulae for the shape, the area, and the activation energy for growth of the crystal nucleus. The formulae facilitate to estimate from the observed shape patterns the parameters of nucleation, to follow the evolution of the crystal nucleus with temperature and the dependence of activation energy on distance between screw dislocations which provide steps on the crystal surface.