Xe exhibits a discrete-row growth mode on the vicinal Pt(997) surface by sequential attachment to the substrate steps. In order to interpret experimental results obtained by grazing incidence helium scattering, potential calculations are performed. A mean-field Hamiltonian within the two-dimensional Ising model is shown to explain the sequential-row growth observed in helium-atom diffraction studies. More specifically, the calculated temperatures for the occurrence of each row depend mainly on the shape of the potential increment due to the steps and countersteps. They are in good agreement with the experimental values associated with maxima in the scattered He intensity versus coverage curves
