The interaction of atoms and molecules with solid surfaces IV―The condensation and evaporation of atoms and molecules

Abstract

The method used in the preceding paper implies that it is only the motion of the adsorbed atom perpendicular to the surface which is changed by the interaction of the solid, and the object of this paper is to remove that restriction and to formulate the method in more general terms. We suppose the adsorbed atom held by one of the atoms of the solid in such a way that it can vibrate relative to it not only radially but also laterally. Whereas in the example worked out in the preceding paper the adsorbed atom could vibrate normally to the surface and migrate freely along it, in the example considered in this paper the adsorbed atom an vibrate radially and laterally but cannot migrate. Owing to the other atoms of the surface, the motion of the adsorbed atom is confined to one side of a plane and the lateral motion can be regarded as taking place on a hemisphere. We suppose that the field of attraction can be represented by a function of the distance from the attraction can be represented by a function of the distance from the attracting centre.