Atom jumping potential-energy wells

This rate law corresponds to an atom jumping out of a potential well by completely breaking i lateral bonds. The transition rate is independent of the energy of the final configuration, i.e, contains no information about the site to which the atom hops, see Figure 1(a). One sets... 

The study of alkali atom reactions with halogen-containing molecules comprises much of the history of reactive scattering in molecular beams. The broad features of the reaction dynamics and their relation to the electronic structure of the potential energy surface are well understood.2 The reaction is initiated by an electron jump transition in which the valence electron of the alkali atom M is transferred to the halogen-containing molecule RX. Subsequent interaction of the alkali ion and the molecule anion, in the exit valley of the potential surface, leads to an alkali halide product molecule MX. 

The periodic arrangement of atoms in a single-crystal surface causes a periodic sequence of potential wells separated by an energy barrier, the activation energy for surface diffusion E (Fig. 1.9). In fact, this barrier depends on the direction of motion, but the adsorbed particle will always jump to a neighboring site along the path of minimum activation energy, which is then... 

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