General impulsive models of scattering of molecules from a solid surface without tangential forces

We propose a general impulsive model for scattering of a system of atoms or ions from a flat solid surface without tangential forces (that is, forces parallel to the surface). It is assumed within the framework of this model that each individual encounter of an atom with the surface is a series of elastic hits of the atom against surface pseudoparticles, the hits instantly following each other. A distinctive feature of the model is that to each atom, one assigns two infinite sequences of masses of pseudoparticles. Criteria for both finiteness and infinity of series of elastic hits are formulated, based on the masses of the pseudoparticles and the mass of the atom. The model is a far-reaching generalization of the well-known “hard-cube model” for scattering of atoms from a solid surface. We illustrate (by some simplest examples related to scattering of potassium iodide molecules) an application of the correlation analysis to the study of the dependence of the dynamical characteristics of the scattering on the masses of the surface pseudoparticles. The absence of tangential forces seems to be a substantial limitation of the model (for instance, the recent experimental data on scattering of KI from a diamond surface indicate that tangential forces play a significant role in this process).